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BY    PROF.   AUGUSTUS    H.    GILL 

OF  THE  MASSACHUSETTS  INSTITUTE  OF    TECHNOLOGY 

^ENGINE  ROOM  CHEMISTRY 
BY  HUBERT   E.   COLLINS 

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THE     POWER     HANDBOOKS 

Engine-Room   Chemistry 

A    COMPEND    FOR    THE 
ENGINEER  AND  ENGINEMAN 


BY 

AUGUSTUS   H.  GILL,  S.B.,  PH.D. 

ASSOCIATE  PROFESSOR  OF  TECHNICAL  ANALYSIS  OF  THE  MASSACHUSETTS  INSTITUTE 

OF  TECHNOLOGY,  BOSTON,  MASS.      AUTHOR  OF  "  GAS  AND  FUEL  ANALYSIS 

FOR  ENGINEERS,"   "A  SHORTHAND  BOOK  OF  OIL  ANALYSIS." 


THIRD  IMPRESSION  —  THIRD  THOUSAND 


Published   by  the 

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CONTENTS 

PAGE 

PREFACE vii 

I     INTRODUCTORY.      Chemical     and     physical     changes. 

Chemical  symbols  explained i 

II     APPARATUS  AND  CHEMICALS.     Specific  heat.    Thermom- 
eter scales.     Chemical  tests 16 

III  FUELS  AND  THEIR  ANALYSIS.    Wood.  Peat.  Coal.  Coke. 

Waste  fuels.  Briquets.  Storage  and  spontaneous 
combustion  of  coal.  Composition  of  fuels.  Methods 
of  analysis.  Sampling.  Determination  of  heating 
value.  Calorimeters.  Berthicr's  method.  Liquid 
fuels.  Fuel  oil.  Gaseous  fuels.  Natural  gas.  Pro- 
ducer and  blast-furnace  gas.  Coal  and  water  gas.  .  41 

IV  THE  REGULATION  OF  COMBUSTION  —  GAS  ANALYSIS. 

Methods  of  burning  coal.  "Fuel  savers."  Samp- 
ling gases.  Orsat  gas  apparatus.  Reagents.  Cal- 
culations —  pounds  of  air  per  pound  of  coal.  Loss 
in  chimney  gases.  Loss  due  to  carbonic  oxide.  Loss 
due  to  unconsumed  carbon  in  the  ash.  Automatic 
apparatus.  Arndt's  econometer.  Custodis  gas  bal- 
ance. Uehling  gas  composimeter.  Ados.  ...  73 
V  WATER,  BOILER  SCALE,  PITTING  AND  CORROSION. 
Hard  water.  Soap  test.  Calculation  of  soda  ash 
necessary  for  softening.  Effects  of  hard  water —  scale, 
corrosion  and  foaming.  Remedies  —  boiler  com- 
pounds. Analysis  of  waters  and  scales.  Experi- 
ments illustrating  hard  water,  eiTect  of  softening 
compounds.  Corrosion  and  pitting  .....  102 
VI  MINERAL  OILS.  Origin.  Distillation  process.  Testing 
of  lubricating  oils.  Viscosity.  Specific  gravity.  Cold 


vi  CONTENTS 

PAGE 

test.  Flash  test.  Fire  test.  Gumming  test.  Acidity 
test.  Test  for  animal  and  vegetable  oils  and  oil  pulp. 
Friction  tests.  Testing  of  burning  oils.  Flash  and 
fire  tests.  Specific  gravity.  Sulphuric  acid  test  .  .  132 
VII  ANIMAL  AND  VEGETABLE  OILS.  Chemical  composition. 
Occurrence.  Methods  of  obtaining  and  refining. 
Methods  of  examination.  Smell.  Specific  gravity. 
Valenta  test.  Elaidin  test.  Maumene  test.  Test  for 
cottonseed  oil,  for  mineral  oils.  Properties  of  the 
various  oils:  castor,  corn,  cottonseed,  horse,  lard, 
linseed,  neatsfoot,  rapeseed,  rosin,  sperm,  tallow, 
turpentine,  whale,  blown,  clock,  Degras,  Moellon, 
neutral,  screw-cutting  and  stainless.  Selection  of 

lubricants 157 

APPENDIX 183 

Tables         

viii  Melting-points  of  salts  and  metals  .  .  .  .  183 
ix  Relation  of  Centigrade  and  Fahrenheit  scales  .  184 
x  Comparison  of  specific  gravity  and  Baume 

degrees 185 

xi   Specific   gravity,    Baume  degrees,  weight  per 

gallon,  and  per  cubic  foot  of  certain  oils     .      186 
xii   Constants  of  certain  oils 187 


PREFACE 

THE  object  of  this  book,  the  substance  of  which  ap- 
peared serially  in  Power,1  is  to  enable  the  engineer  or 
engineman  to  gain  some  familiarity  with  the  properties 
and  behavior  of  the  substances,  as  fuel,  water  and  oil, 
in  which  he  is  vitally  interested,  and  some  suggestions 
and  assistance  in  connection  with  their  use. 

A  knowledge  of  chemistry  and  physics,  such  as  may 
be  obtained  from  the  "Science  Primers"2  or  a  high 
school  course,  is  very  desirable,  one  might  almost  say 
indispensable.  Chapter  I  will  serve  as  a  review  of 
certain  topics  from  these  branches  of  science. 

A  careful  study  of  the  applications  of  fuel,  water,  and 
lubricants  cannot  but  result  in  increased  economy  in 
their  use,  and  if  this  little  book  renders  this  study  easy 
the  writer's  purpose  will  have  been  accomplished. 

The  apparatus  can  be  obtained  from  the  leading 
dealers  in  New  York  City. 

BOSTON,  MASS.,  July,  1907.  AUGUSTUS  H.  GILL. 


1  Power,  May,  1905,  to  July,  1906. 

2  " Chemistry,"  H.  E.  Roscoe;  "Physics,"  Balfour  Stewart.     American  Book 
Company,  New  York. 


LIST    OF    ILLUSTRATIONS 

FIGURE  PAGE 

1.  Iron  Mortar 16 

2.  Horn  Pan  Scales 17 

3.  IOOO-CG.  Graduate ...  18 

4.  Graduated  Flask 19 

5.  Burette 20 

6.  Bunsen  Burner 20 

7.  Blowpipe 21 

8.  Crucible 22 

9.  Porcelain  Dish 23 

10.     Test-tube 24 

n.     Beakers 25 

12.  Wash-bottle 25 

13.  Iron  Stand 26 

14.  Melting-point  Boxes 28 

15.  Otto-Hoffman  Coke  Oven.     Longitudinal  Section       .      .  48 

1 6.  Otto-Hoffman  Coke  Oven.     Cross  Section       ....  49 

17.  Otto-Hoffman  Coke  Oven.     General  Perspective       .      .  49 

18.  Semet-Solvay  Coke  Oven 50 

19.  William  Thomson's  Calorimeter ,  58 

20.  Barrus's  Calorimeter 59 

21.  Lewis  Thompson's  Calorimeter 60 

22.  Parr's  Calorimeter 61 

23.  Norton's  Calorimeter 62 

24.  Taylor  Gas  Producer 68 

25.  Arrangement  of  Apparatus  /to  take  a  Sample  of  Gas  .  76 
26.-  Orsat's  Gas  Apparatus 78 

Bunte's  Chart 93 

Arndt's  Econometer 95 

ix 


x  LIST    OF    ILLUSTRATIONS 

FIGURE  PAGE 

29.  Custodis  Gas  Balance        .            96 

30.  Uehling's  Gas  Composimeter.     Diagram 97 

31.  Uehling's  Gas  Composimeter 98 

32.  General  Corrosion .no 

33.  Pitting  of  Iron         112 

34.  Carbonic  Acid  Generator 122 

35.  Cheese-box  Still.     Cross  Section 133 

36.  Plan  of  Cheese-box  Still 133 

37.  Horizontal  Still 134 

38.  Horizontal  Still.     Cross  Section 134 

39.  Condenser    . 135 

40.  Saybolt  Viscosimeter 139 

41.  Baume  Hydrometer 141 

42.  Stem  of  Baume  Hydrometer 142 

43.  Flash-point  Apparatus  for  Lubricating  Oils    .      .      .      .  144 

44.  New  York  State  Tester 150 

45.  Thurston's  Oil  Friction  Testing  Machine 154 

46.  Thurston's  Friction  Testing  Machine 155 

47.  Flash-point  Apparatus  for  Lubricating  Oils.    Details     .  188 


I 


INTRODUCTORY  — CHEMICAL  AND  PHYSICAL 
CHANGES— CHEMICAL  SYMBOLS   EXPLAINED 

THE  two  terms  "chemistry"  and  "physics"  can  per- 
haps be  best  defined  by  saying  that  chemistry  has  to 
do  with  chemical  changes,  or  is  the  science  of  chemical 
changes,  whereas  physics  deals  with  physical  changes. 
A  chemical  change  is  one  in  which  the  nature  of  the  sub- 
stance is  altered.  For  example,  when  iron  is  changed 
by  exposure  to  iron  rust  it  is  changed  chemically;  we 
can  no  longer  recognize  any  semblance  of  metallic  iron 
in  the  reddish-brown  powder  before  us,  nor  can  we  by 
mechanical  means  get  the  bright  metallic  iron  back 
again;  chemical  means  must  be  employed.  On  the 
other  hand,  a  piece  of  iron  may  be  chipped  or  filed  — 
reduced  to  powder;  but  it  still  retains  its  metallic  ap- 
pearance or  luster,  and  may  by  melting  and  working 
be  brought  back  to  its  original  form.  In  other  words, 
through  all  these  processes  it  always  remains  iron; 
hence  it  is  changed  physically,  not  chemically.  Again, 
we  may  mix  iron  filings  and  finely  powdered  sulphur, 
obtaining  a  powder  resembling  neither:  it  is  only  a 
mechanical  mixture.  This  can  be  shown  by  separat- 
ing the  iron  by  a  magnet,  or  the  sulphur  by  solu- 


2  ENGINE-ROOM    CHEMISTRY 

tion  *  in  carbon  bisulphide:  if  we  heat  some  of  the 
mixture  it  begins  to  glow,  the  glow  extends  through- 
out the  mass,  and,  after  cooling,  on  examination  we 
find  a  fused  substance  which  is  neither  magnetic  nor 
soluble  in  carbon  bisulphide,  and  from  which  the  iron 
and  sulphur  can  be  separated  only  by  chemical  pro- 
cesses —  a  chemical  compound,  sulphide  of  iron. 

Other  examples  of  chemical  changes  will  no  doubt 
present  themselves  on  reflection,  e.g.,  the  "souring"  of 
milk  and  cider;  the  fermentation  of  beer,  in  which 
sugar  or  molasses  is  changed  to  alcohol  and  carbonic 
acid;  the  burning  of  fuel,  etc.  Physical  changes  are 
seen  in  the  drilling  and  bending  of  metals,  the  melting 
of  lead  and  solder,  the  breaking  of  stone,  etc.  Chem- 
istry is  sometimes  spoken  of  as  the  science  that  deals 
with  atoms,  while  physics  deals  with  molecules:  this  is 
another  way  of  saying  that  these  are  the  units  with 
which  these  two  sciences  largely  deal.  By  "molecule" 
we  understand  the  smallest  particle  of  a  substance  that 
can  exist  by  itself  and  be  that  substance;  while  an 
atom  is  the  smallest  particle  of  a  substance  that  can 
exist  in  combination  with  other  atoms,  either  like  or 
unlike.  Molecules  are  made  up  of  atoms  which  are 
either  similar  or  dissimilar;  and  all  substances  are 

1  By  the  term  "solution"  is  meant  the  division  of  the  particles  of  a  solid  among 
the  particles  of  a  liquid,  so  that  the  former  become  invisible  and  cannot  be  separated 
by  filtering,  that  is,  straining  through  filter  paper.  By  evaporation,  or  boiling  off  the 
liquid,  the  solid  is  recovered  again  unchanged.  This  is  known  as  physical  solution. 
When,  in  making  soldering  fluid,  zinc  is  "dissolved"  or  "cut"  with  muriatic  acid, 
that  is  said  to  be  a  chemical  solution,  because  on  its  evaporation  a  different  sub- 
stance from  zinc  —  a  white  solid,  zinc  chloride  —  is  obtained.  When  oil  is  mixed 
with  water  an  emulsion  like  milk  is  obtained,  which  in  time  separates.  So  when  clay 
is  mingled  with  water,  a  suspension  rather  than  solution  is  produced,  because  after 
a  time  the  clay  settles  out. 


INTRODUCTORY  3 

made  up  of  molecules.  If  the  atoms  that  go  to  make 
up  a  molecule  are  of  the  same  kind,  the  substance  com- 
posed of  such  molecules  is  said  to  be  an  elementary 
substance  or  an  element.  Such  are:  the  metals,  as 
iron  and  copper;  the  non-metals,  as  sulphur  and  car- 
bon (seen  in  charcoal) ;  the  gases,  as  oxygen  and  nitro- 
gen (existing  mixed  in  the  air);  and  some  seventy 
others.  On  the  other  hand,  if  the  atoms  making  up  a 
molecule  are  unlike,  the  substance  is  said  to  be  a  com- 
pound. This  is  illustrated  in  sulphide  of  iron,  car- 
bonic acid,  and  practically  all  the  substances  with 
which  we  come  in  contact. 

Besides  writing  "sulphide  of  iron/'  "carbon,"  "sul- 
phur," etc.,  chemists  are  in  the  habit  of  designating  all 
substances  elementary  and  compound,  as  far  as  pos- 
sible, by  symbols.  These  symbols  mean  very  much 
more  than  the  "ferr.  sulph.,"  "pot.  nitr.,"  or  other 
abbreviations  of  the  apothecary:  they  show,  by  a 
small  figure  written  after  the  element  and  below  the 
line,  the  number  of  atoms  of  each  element  in  the  sub- 
stance, and,  as  each  of  these  atoms  has  a  definite 
weight,  the  percentage  of  each  element  present.  More- 
over, in  the  case  of  what  are  called  "displayed"  or 
"graphic  symbols,"  they  show  the  way  and  manner  in 
which  the  various  atoms  are  combined  with  each  other, 
or,  in  other  words,  the  constitution  of  the  substance.  In 
the  case  of  gases,  the  symbol  shows  furthermore  their 
volumetric  composition.  For  example,  the  sulphide  of 
iron  mentioned  above  has  the  formula  or  symbol  FeS; 
but  as  there  are  other  combinations  of  iron  and  sulphur 
to  which  the  term  "sulphide  of  iron"  is  equally  appli- 


ENGINE-ROOM    CHEMISTRY 


cable,  as  FeS2  and  Fe2S3,  the  symbol  FeS  states  just 
which  this  one  is,  namely,  ferrous  sulphide.  It  indi- 
cates furthermore  that  it  is  composed  of  one  atom  of 
iron  and  one  atom  of  sulphur,  or  56  parts  by  weight  of 

iron  and  32  parts  by  weight  of  sulphur,  or — - — 7  =•-—, 

32  +  50     88 

or  63.6  per  cent,  iron,  and  |f  or  36.3  per  cent,  of  sul- 
phur. In  the  case  of  sulphurous  acid,  SO2,  the  form- 
ula shows  it  to  be  made  up  of  one  atom  of  sulphur 
combined  with  two  atoms  of  oxygen,  whence  it  receives 
the  exact  name  of  sulphur  dioxide  (di  =  Greek  word 
for  "two")  or  32  parts  of  sulphur  and  32  parts  of  oxy- 
gen, or  If  or  50  per  cent,  of  sulphur  and  f-j  or  50  per 
cent,  oxygen.  Besides  this,  the  symbol  shows  it  to 
be  composed  of  one  double  volume  of  sulphur  vapor 
with  two  double  volumes  of  oxygen  gas,  making  two 
double  volumes  of  sulphur  dioxide. 


I 
so. 


So  it  is  with  every  definite  chemical  compound.  These 
weights  of  the  elements,  with  which  we  have  been  deal- 
ing, in  which  they  combine,  are  spoken  of  as  atomic 
weights.  The  story  of  their  determination  would  take 
us  beyond  the  limits  of  the  present  work.  Suffice  it  to 
say  that  they  are  fixed  by  extremely  careful  analyses 
of  absolutely  pure  compounds  containing  the  element 
the  atomic  weight  of  which  is  to  be  determined. 


INTRODUCTORY 


Table  I  gives  the  list  of  the  elements  with  whose 
compounds  we  are  likely  to  meet,  together  with  their 
atomic  weights. 

TABLE  I 
LIST  OF  COMMON  ELEMENTS  AND  THEIR  ATOMIC  WEIGHTS 


Element 

Symbol 

Atomic 
Weight 

Source  ' 

Familiar  Compound 

Aluminum 

Al 

27.1 

Clay 

Alum 

Barium 

Ba 

1374 

Barytes 

Barium  chloride 

Calcium 

Ca 

40.1 

Lime 

Gypsum,  chalk,  marble 

Carbon 

C 

12.0 

Charcoal 

Graphite,  diamond 

Chlorine 

Cl 

35  -5 

Salt 

Chlorides,  salt 

Copper 

Cu 

63.6 

Native 

Copper  sulphate,  "blue- 

(Latin,  cuprum} 

copper 

stone  " 

Hydrogen 

H 

I.O 

Water 

Hydrates 

Iron 

Fe 

55-9 

Iron  ore 

Iron  rust 

(Lat.  ferrum) 

Lead 

Pb 

206.9 

Galena 

Lead    acetate,    sugar    of 

(Lat.  plumbum) 

lead 

Magnesium 

Mg 

24.4 

Chloride 

Magnesite,  Epsom  salts 

Mercury 

Hg 

200.0 

Sulphide 

Calomel,    corrosive    sub- 

(Hydrargyrum) 

limate 

Nitrogen 

N 

14.0 

Air 

Oxygen 

0 

16.0 

Air 

Phosphorus 

P 

31.0 

Bones 

Phosphates 

Potassium 

K 

39-i 

Potash 

Niter 

(Lat.  kalium) 

Sodium 

Na 

23.0 

Salt 

Soda  ash,  salt 

(Lat.  natrium) 

Sulphur 

S 

32.0 

Native 

Brimstone 

sulphur 

Zinc 

Zn 

654 

Zinc  white 

ENGINE-ROOM    CHEMISTRY 


Table   II   shows  some  of  the  more  common  com- 
pounds containing  the  above  elements. 

TABLE   II 


Symbol 

Chemical  Name 

Popular  Name 

Al2O3+SiO2  +  H2O 

Aluminum  silicate 

Clay 

K2A12(S04)4+24H20 

Aluminum  and   potas- 

sium sulphate 

Potash  alum 

BaS04 

Barium  sulphate 

Barytes 

CaSO4+2H2O 

Calcium  sulphate  hy- 

drated 

Gypsum 

CaS04 

Calcium  sulphate 

Plaster  of  Paris 

CaO 

Calcium  oxide 

Lime 

CaO2H2 

Calcium  hydrate 

Air-slaked  lime 

CaC03 

Calcium  carbonate 

Chalk,  limestone,  mar- 

ble 

CaH2(C03)2 

Calcium  bicarbonate 

Bicarbonate  of  lime 

CaCl2 

Calcium  chloride 

Same 

CO 

Carbon  monoxide 

"  After    damp,"     car- 

bonic oxide 

CO2 

Carbon  dioxide 

"Whitedamp,"  "choke 

damp,"       carbonic 

acid 

HC1 

Hydrochloric  acid 

Muriatic  acid 

CaC1*+-CaOCl   1 
CaCl202~          Cl2J 

f  Calcium  chloride 
[  Calcium  hypochlorite 

|  Chloride  of  lime 
[  Bleaching  powder 

H20 

Hydric  oxide 

Water 

Fe203 

Ferric  oxide 

Iron  rust 

Fe304 

Ferroso-ferric  oxide 

Forge  scale 

FeC03 

Ferrous  carbonate 

Carbonate  of  iron 

FeH2(C03)2 

Ferrous  bicarbonate 

Bicarbonate  of  iron 

PbC03 

Lead  carbonate 

White  lead 

PbO 

Lead  oxide 

Litharge 

MgO 

Magnesium  oxide 

Calcined  magnesia 

MgC03 

Magnesium  carbonate 

Magnesite,  magnesia 

INTRODUCTORY 
TABLE    II  —  Continued 


Symbol 

Chemical  Name 

Popular  Name 

MgH2(C03)2 

Magnesium     bicarbo- 

Bicarbonate   of  mag- 

nate 

nesia 

MgCl2 

Magnesium  chloride 

Same 

HNO3 

Nitric  acid 

Aqua  fortis 

NH3 

Ammonia 

Ammonia 

Ca3P208 

Calcium  phosphate 

Bones 

KNO3 

Potassium  nitrate 

Niter 

K2C03 

Potassium  carbonate 

Potash  or  pearl  ash 

KOH 

Potassium  hydrate 

Potash     lye,      caustic 

potash 

NaCl 

Sodium  chloride 

Salt 

Na2CO3  +  H2O 

Sodium  carbonate  hy- 

Washing    soda,    soda 

drated 

crystals 

Na2C03 

Sodium  carbonate 

Soda  ash 

NaHCO3 

Sodium  bicarbonate 

Baking  soda 

NaOH 

Sodium  hydrate 

Soda  lye,  caustic  soda 

S02 

Sulphur  dioxide 

Sulphur    fumes,     sul- 

phurous acid 

H2S04 

Sulphuric  acid 

Oil  of  vitriol 

A  point  to  be  observed  in  this  connection  is  that  the 
elements  combine  in  certain  definite  proportions.  Re- 
verting to  our  experiment  of  heating  sulphur  and  iron 
together,  if  we  were  to  mix  56  ounces  or  pounds  of 
sulphur  with  56  ounces  or  pounds  of  iron  and  heat 
them,  we  should  find,  after  the  reaction  was  finished, 
that  there  was  a  residue  of  uncombined  sulphur  amount- 
ing to  24  ounces  or  pounds  as  the  case  might  be.  So 
that  the  proper  mixture  would  be  56  parts  of  iron  to 


8  ENGINE-ROOM    CHEMISTRY 

32  parts  of  sulphur,  any  excess  of  either  being  left  un- 
combined. 

Chemical  Reactions  or  Equations.  —  In  all  the 
text-books  of  chemistry,  one  finds  expressions  like 
this,  Fe  +  S  =  FeS,  which  is  the  chemist's  way  of 
saying  that  when  iron  (Fe)  and  sulphur  (S)  unite  under 
certain  circumstances,  ferrous  sulphide  (FeS)  results. 
From  what  has  been  stated  in  the  preceding  paragraph, 
more  than  this  is,  however,  here  expressed;  namely, 
that  when  56  parts  by  weight,  be  they  ounces,  pounds, 
or  grams  of  iron,  and  32  parts  by  weight  of  sulphur 
combine,  88  parts  by  weight  of  ferrous  sulphide  are 
produced. 

Every  simple  chemical  action  can  be  thus  expressed. 
It  is  a  question  of  determining  what  factors  enter  into 
the  action  and  what  products  are  formed,  then  total- 
ing them  on  each  side,  and  putting  the  sign  of  equal- 
ity between  the  sum  of  the  factors  and  the  sum  of  the 
products.  For  example,  when  lime  (quicklime)  ab- 
sorbs water  from  the  air  and  makes  "air-slaked  lime" 

CaO      +   H20   =        Ca02H2 
quicklime       water      air-slaked  lime 
40  +  16  +  (2  +16)  =  40  +  (2  X  1 6)  +  (2X1) 
56  +  18  =  74 

These  equations  tell  us  further,  how  much  of  one  sub- 
stance (quicklime)  must  be  used  to  absorb  the  other 
(water),  and  how  much  air-slaked  lime  will  be  pro- 
duced. Reading  this  equation  we  see  that,  to  absorb 
1 8  pounds  of  water,  56  pounds  of  quicklime  must  be 
employed,  and  that  74  pounds  of  slaked  lime  would  be 
produced.  If  it  were  a  question  of  absorbing  100 


INTRODUCTORY  9 

pounds  of  water,  we  could  make  the  proportion, 
weight  of  water  :  weight  of  quicklime  needed  :: 
molecular  weight  of  water  :  molecular  weight  of 
quicklime,  or  100  :  x  ::  18  :  56.  Whence  \8x=  5600. 
x  =  311+  lb. 

In  looking  over  Table  II  we  see  some  compounds 
designated  as  acids,  e.g.,  HC1,  hydrochloric  acid; 
H2SO4,  sulphuric  acid;  HNO3,  nitric  acid;  and  the  ques- 
tion may  very  properly  arise,  what  an  acid  is.  Chem- 
ically speaking  an  acid  is  a  compound  of  hydrogen,  a 
non-metallic  element  and  usually  oxygen:  this  hydro- 
gen is  replaceable  by  a  metal,  forming  a  salt.  Acids 
generally  have  a  sour  taste  and  turn  blue  litmus  paper 
red.  When  "soldering  acid"  is  made  by  " dissolving" 
zinc  in  muriatic  acid,  bubbles  of  gas  are  given  off, 
which  are  the  hydrogen  that  is  replaced  by  the  zinc; 
and  if  we  were  to  evaporate  the  liquid  resulting,  we 
should  get  a  white  solid,  "muriate  of  zinc"  or  zinc 
chloride.  Exactly  opposite  in  character  to  the  acids 
are  the  bases,  which  they  resemble  in  containing  hydro- 
gen and  oxygen;  but  in  place  of  the  non-metallic  or 
negative  element  they  have  a  metallic  or  positive  ele- 
ment. Such  in  the  table  are:  CaO2H2,  air-slaked  lime 
or  calcium  hydrate;  KOH,  caustic  potash  or  potassium 
hydrate;  NaOH,  caustic  soda  or  sodium  hydrate. 
They  have  a  biting  taste,  a  "soapy  feel"  -actually 
dissolving  the  skin  —  and  turn  red  litmus  blue.  They 
unite  with  acids,  forming  salts:  if  we  neutralize  caustic 
soda  with  muriatic  acid  and  evaporate  the  solution 
obtained,  we  get  common  salt.  We  can  conversely 
obtain  the  base  from  common  salt  by  the  electric  cur- 


10  ENGINE-ROOM    CHEMISTRY 

rent,  as  is  done  on  an  enormous  scale  for  paper-makers 
and  others. 
Again,  on  inspecting  Table  II  we  notice 

CaCl2  NaCI 

CaO2H2        NaOH        KOH        CaCO3        Na2CO3        K2CO3 

Why  this  diversity  of  numbers?  It  is  due  to  the  fact 
that  the  elements  calcium  (Ca), sodium  (Na),and  potas- 
sium (K)  have  a  different  replacing  power  as  regards 
hydrogen.  That  is,  while  sodium  (Na)  replaces  one 
atom  of  hydrogen  (H)  in  HC1,  calcium  (Ca)  replaces 
two  atoms  in  two  molecules  of  HC1,  2HC1  or  H2C12. 
Sodium  is  said  to  be  univalent,  that  is,  worth  one  (uni 
=  one,  valeo  =  to  be  worth),  or  will  replace  or  com- 
bine with  one  atom  of  hydrogen  or  chlorine;  similarly, 
calcium  is  bivalent  (bi  =  two),  iron  is  trivalent  (tri  = 
three),  and  carbon  is  quadrivalent  (quadri  —four). 
Other  univalent  elements  in  the  table  are  chlorine 
and  hydrogen:  bivalent  elements  are  barium,  calcium, 
copper,  lead,  magnesium,  mercury,  oxygen,  and  zinc; 
trivalent  elements  are  aluminum,  iron,  nitrogen,  and 
phosphorus;  quadrivalent  elements  are  carbon  and 
silicon. 

CaCO3  Na2CO3  K2CO3 

CaCl2  NaCI 

In  this  case,  the  diversity  of  numbers  is  due  to  the 
fact  that  in  addition  to  elements  like  sodium  and 
calcium,  which  are  univalent  and  bivalent,  that  is,  re- 
place respectively  one  atom  and  two  atoms  of  hydro- 
gen, we  have  acids  corresponding,  which  have  one  atom 


INTRODUCTORY  II 

and  two  atoms  of  hydrogen  which  can  be  replaced: 
such  acids  are  said  to  be  monobasic  (memo  =  one)  and 
dibasic  (di  =  two).  When  a  bivalent  element,  as  cal- 
cium (Ca),  combines  with  a  dibasic  acid  as  carbonic 
H2CO3,  both  atoms  of  hydrogen  are  replaced  and  we 
get  a  salt  CaCO3,  so  CaSO4,  BaSO4,  MgCO3,  etc.  When 
a  univalent  element  Na'  so  combines,  two  atoms  of 
the  element  Na/  are  required  to  form  a  neutral  salt 
Na2CO3,  so  K2CO3;  sometimes  only  one  hydrogen  atom 
replaced  and  we  get  an  acid  salt  NaHCO3.  When  a 
univalent  element,  as  sodium  (Na),  combines  with  a 
monobasic  acid,  as  hydrochloric  (HC1),  one  atom  of 
hydrogen  is  replaced  and  we  get  a  salt,  NaCl,  so  KC1, 
KNO3,  etc.;  when  a  bivalent  element  (Ca")  combines 
with  a  monobasic  acid  two  molecules  of  acid  (H2C12) 
are  required  to  form  a  salt,  CaQ2,  so  MgCl2. 

It  will  be  observed  that  in  the  foregoing,  all  refer- 
ences have  been  made  to  minerals  or  metals,  all  illus- 
trations have  been  taken  from  "inorganic  chemistry" 
as  it  is  termed.  There  is  another  branch  of  the  science, 
which,  from  its  intimate  connection  with  organized 
life,  is  designated  "organic  chemistry."  It  was  for- 
merly supposed  that  for  the  production  of  its  com- 
pounds, life  of  some  kind  was  necessary,  and  that  they 
could  not  be  made  in  the  laboratory  from  inorganic 


materials.     In  1828  Woehler  made  urea,  C(X  a 

NH2 

substance  known  only  to  occur  in  urine,  by  heating  am- 
monium cyanate  (NH4CNO),  an  inorganic  compound. 


12  ENGINE-ROOM    CHEMISTRY 

He  was  the  first  to  erase  the  hard  and  fast  line  separat- 
ing these  two  subdivisions;  it  is  better  termed  the 
chemistry  of  the  carbon  compounds.  Carbon  not  only 
combines  with  other  elements  as  do  other  elements, 
but  it  possesses  the  property  of  combining  with  itself 
to  a  very  marked  degree.  Its  combination  with  hy- 
drogen, CH4,  is  known  as  marsh  gas  or  the  "fire  damp" 
of  mines;  another,  CH3  -  CH2  -  CH2  -  CH2  -  CH2 
CH3  =  C6H14,  a  liquid,  is  the  chief  constituent  of 
gasolene,  and  still  another,  CH3  —  CH2,  —  etc.  —  CH3  = 
C24H50,  a  solid,  is  contained  in  paraffin  wax.  The  com- 
pounds between  C6H14  and  C24H50  occur  in  the  kerosenes 
and  the  mineral  lubricating  oils. 

Organic  Chemistry  is  the  chemistry  of  the  necessities 
of  life  —  food,  clothing,  and  raiment  —  of  digestion, 
assimilation,  growth,  and  decay,  and  of  the  accessories 
of  life,  as  the  alcoholic  beverages,  the  brilliant  aniline 
dyes  and  the  perfumes. 

Chemical  Analysis  is  divided  into  two  parts: 

(1)  Qualitative  Analysis,  in  which  the  components 
of  a  substance  are  determined,  and  which  answers  the 
question  "Of  what  is  a  substance  composed?"  and 

(2)  Quantitative  Analysis,  in  which  the  percentages 
of  these  components  are  fixed. 

While  it  is  possible  to  determine  with  reasonable 
accuracy  the  elements  and  their  percentages  which 
make  up  certain  compounds,  as  a  boiler  scale  or  an 
alloy,  or  "of  something  of  a  mineral  or  metallic  sub- 
stance" or  inorganic  bodies,  such  is  not  always  the 
case  with  compounds  containing  carbon  or  organic  sub- 
stances. For  example,  it  is  practically  impossible  to 


INTRODUCTORY  13 

ascertain  to  what  extent  an  asphalt  paint  is  adulter- 
ated with  gas,  wood,  or  petroleum  tar. 

This  brings  me  to  speak  of  the  two  subdivisions  of 
both  qualitative  and  quantitative  analysis  —  ultimate 
and  proximate.  An  ultimate  analysis  states  simply 
the  percentages  of  the  various  elements  present,  while 
a  proximate  analysis  states  the  substances  of  which  it 
is  composed.  For  example,  the  ultimate  analysis  of  a 
white  powder  shows  it  to  contain  carbon,  hydrogen, 
and  oxygen  in  certain  percentages.  This  tells  little 
of  practical  value  about  it.  By  suitable  means,  how- 
ever, we  ascertain  that  it  is  made  up  of  50  per  cent, 
starch  and  50  per  cent,  sugar,  and  no  one  would  have 
the  slightest  trouble  in  duplicating  it. 

The  principle  in  the  qualitative  analysis  of  sub- 
stances consists  in  the  production  either  of  a  definite 
precipitate  or  "sediment"  containing  the  element 
sought,  or  of  a  colored  compound,  or  both,  which  can 
only  be  formed  when  the  element  in  question  is  present. 

In  quantitative  analysis  a  substance  is  estimated  in 
two  ways:  (i)  by  weighing  it,  gravimetric  analysis; 
(2)  by  measuring  it,  volumetric  analysis,  or  rather  by 
measuring  an  acid  or  alkali  necessary  to  neutralize  or 
dissolve  it. 

(i)  In  gravimetric  analysis  a  weighed  amount  of 
the  substance  is  precipitated  under  definite  conditions, 
forming  a  compound  of  definite  composition  which  is 
not  dissolved  by  the  liquids  in  which  it  is  formed. 
This  compound  is  filtered  off,  "strained"  through  spe- 
cially prepared  paper  which  collects  it  completely,  the 
paper  burned  and  compound  heated,  often  to  redness, 


14  ENGINE-ROOM    CHEMISTRY 

giving  a  compound  of  definite  composition  free  from 
water.  This  is  weighed,  and  from  its  known  composi- 
tion, the  amount  of  the  element  sought,  calculated, 
whence  its  percentage  in  the  substance  under  exami- 
nation can  be  found.  For  example,  to  estimate  the 
amount  of  lime  in  a  boiler  scale,  the  scale  is  dissolved 
in  pure  muriatic  acid,  the  solutions  boiled  down  com- 
pletely or,  as  the  chemist  says,  evaporated  to  dryness, 
heated  to  render  silica  (sandy  matters)  insoluble,  re- 
dissolved  in  water  with  the  addition  of  acid  by  heat- 
ing, and  neutralized  with  ammonia:  this  throws  down 
any  iron  or  alumina  (clayey  matters)  that  might  be 
present,  leaving  in  solution  nothing  but  lime,  mag- 
nesia, soda,  and  potash.  Under  these  conditions,  if 
ammonium  oxalate  be  added,  oxalate  of  lime  (calcium 
oxalate)  and  nothing  else  is  thrown  down,  and,  as  it  is 
not  dissolved  by  the  liquid  present,  the  lime  is 
precipitated  completely.  The  precipitate  of  calcium 
oxalate  is  collected  on  a  filter,  the  filter  burned 
in  a  weighed  crucible,  the  precipitate  heated  to 
a  white  heat,  whereby  it  is  changed  to  quicklime 
and  weighed.  The  gain  in  weight  after  deducting 
the  filter  ash  represents  the  amount  of  lime  (calcium 
oxide)  in  the  scale. 

(2)  Volumetric  Analysis.  An  example  of  the  appli- 
cation of  volumetric  analysis  is  found  in  the  determina- 
tion of  the  alkaline  strength  of  caustic  soda.  A 
weighed  amount  is  dissolved  in  water  in  a  flask,  litmus 
solution  added,  and  standard  hydrochloric  acid  run  in 
from  a  burette  or  measuring-tube  until  the  solution 
turns  faintly  red.  As  every  cubic  centimeter  of  the 


INTRODUCTORY  15 

acid  corresponds  to  a  definite  amount  of  caustic  soda 
or  will  neutralize  it,  from  the  amount  of  acid  used,  the 
amount  of  caustic  present  can  be  calculated.  This 
kind  of  analysis  is  rapid  and  accurate,  and  it  has  a  very 
wide  application. 


II 


APPARATUS  AND  CHEMICALS —  CHEMICAL 
TESTS 

SOME  one  has  said  that  it  is  not  sufficient  to  know 
the  principles  of  a  science:  one  must  also  be  able  to 
manipulate  or  handle  the  tools.  The  tools  which 
the  chemist  uses  are  very  varied  and  comprehensive, 
including  not  only  those  usually  employed  by  all 
mechanics,  but  also  those  peculiarly  his  own  —  the 
delicate  balance  and  the  powerful  crusher,  strong  acids 
and  alkalies,  and  the  means  of  production  of  intense 
heat  as  the  gas-burner  and  even  the  electric  furnace. 


FIG.  i.  — Iron 
Mortar 

Sampling  and  Grinding  Apparatus.  —  The  ordinary 
coffee-mill  set  fine  will  serve  to  grind  coal  finely  enough 
for  the  moisture  determination.  For  calorimetric  or 
chemical  tests  it  should  be  ground  three  times  in  the 
mill  and  finished  by  grinding  in  a  5~in.  iron  mortar 
(Fig.  i),  and  passed  through  a  loo-mesh  sieve.  Any 

16 


APPARATUS    AND    CHEMICALS  17 

particles  remaining  on  the  sieve  should  not  be  thrown 
away,  but  should  be  returned  to  the  mortar  and  re- 
ground. 

A  4-in.  palette  knife  is  very  useful  for  handling  and 
weighing  out  these  powdered  samples. 

Weighing  Apparatus.  —  For  the  necessities  of  this 
book  the  weighing  can  be  done. on  horn  pan  or  photo- 
graphic scales  with  7J-in.  beam  (Fig.  2),  with  metric 
weights  to  100  grams.  They  consist  of  a  beam,  from 


FIG.  2.  —  Horn  Pan  Scales 

each  end  of  which  a  horn  pan  is  suspended  by  means  of 
silk  threads.  The  beam  is  provided  with  a  pointer; 
and  the  scales  are  sensitive  to  o.oi  gram,  that  is,  they 
will  show  differences  of  o.oi  gram.  The  weights  from 
this  up  to  100  grams  are  contained  in  a  wooden  block. 
To  protect  the  scales  from  drafts  they  may  be  hung 
inside  a  box. 

The  operation  of  weighing  is  conducted  by  laying 
the  substance  to  be  weighed  on  the  left-hand  pan  and 
placing  the  weights  on  the  other  —  handling  them 


i8 


ENGINE-ROOM    CHEMISTRY 


with  pincers  to  prevent  them  from  being  corroded.  To 
save  time,  the  weights  are  always  placed  on  the  pan  in 
regular  order,  beginning  with  the  heaviest  that  it  is 
judged  that  the  object  will  weigh;  and  the  operation 
is  continued  until  the  scales  just  balance,  or,  better, 
swing  to  the  same  distance  each  side  of  the  stirrup 
which  supports  them.  The  weight  of  the  substance  is 
read  off  from  the  block,  set  down  in  a  note-book  pro- 
vided for  this  purpose  —  not  on  loose  paper  —  and  is 
checked  by  putting  each  weight  into  its  proper  place. 

For  heavier  objects,  scales  of  the  type  of  a  grocer's 
small  tea  scales,  with  porcelain  plate  may  be  recom- 
mended. 

Measuring  Apparatus.  —  Liquids  are  measured  by 
graduates  for  coarse  work,  and  by  graduated  flasks, 


i 


FIG.  3.— 

IOOO-CC. 

Graduate 


burettes,  and  pipettes  for  accurate  work.  Graduates 
(Fig.  3)  are  tall  graduated  tubes  with  a  lip  for  pouring 
and  a  foot  upon  which  they  stand.  Those  holding  50 
cubic  centimeters  (cc.)  are  most  convenient:  they  are 
to  be  had  in  various  sizes  to  a  liter  (1000  cc.). 


APPARATUS    AND    CHEMICALS  19 

Graduated  flasks  (Fig.  4)  have  a  line  upon  their 
necks  which  shows  the  hight  to  which  they  must  be 
filled  to  contain  a  certain  quantity,  as  a  fluid  ounce, 
or  more  usually  cubic  centimeters.  They  should  be 
filled  so  that  the  lowest  part  of  the  curve  which  the 
liquid  assumes — the  meniscus  —  just  touches  the  line. 


FIG.  4.— 

Graduated 

Flask 

A  50-cc.  flask  will  be  required  to  measure  the  water 
for  the  hardness  test. 

A  burette  (Fig.  5)  is  a  tube  graduated  like  an  engi- 
neer's scale  into  whole  divisions  and  tenths,  usually 
into  cubic  centimeters  and  tenths,  and  provided  with 
an  outlet  at  the  bottom  closed  by  a  glass  stopcock,  or 
ball  valve  and  jet.  By  pinching  the  rubber  tube  en- 
closing the  ball  valve,  a  channel  is  made  for  the  liquid 
to  run  out.  The  burette  is  held  by  a  clamp  in  a  ver- 
tical position  and  the  liquid  read  in  the  same  way  as  in 
the  case  of  the  graduated  flask.  The  apparatus  is 
filled  with  the  standard  solution  of  soap  by  pouring  it 
in  through  a  funnel. 


20 


ENGINE-ROOM    CHEMISTRY 


FIG.  5. 
—  Bu- 
rette 


Apparatus  for  the  Production  and  Application  of  Heat. 

—  Lamps  and  Burners.  Where  available,  gas  is  the  most 
satisfactory  source  of  heat  and  is  burned  in  the  Bunsen 


FIG.  6.  —  Bunsen 
Burner 

burner  (Fig.  6).  This  consists  of  a  straight  tube  provided 
with  air  inlets  near  the  bottom.  The  gas,  entering  by  a 
jet  at  the  center  of  the  tube,  sucks  the  air  necessary  for 


APPARATUS    AND    CHEMICALS  21 

its  combustion  through  these  inlets  and  burns  with  a  col- 
orless flame,  giving  a  temperature  of  about  2300  deg.  F. 
Where  gas  is  not  obtainable,  some  form  of  vaporizing 
gasolene  burner,  as  seen  in  the  plumber's  furnace  or 
lamp  for  soldering,  can  be  used  to  good  advantage. 
These  employ  the  same  principle  as  the  gas-burner: 
the  gasolene  is  forced  by  air-pressure  through  a  hot  coil 
of  pipe  which  changes  it  to  vapor,  and  this  mixes  with 
air  and  burns  like  a  fixed  gas.  Instead  of  these,  the 
common  alcohol  lamp  may  be  used  for  most  purposes. 


FIG.  7.— 
Blowpipe 

Blowpipes.  These  (Fig.  7)  consist  of  a  tube  bent 
as  in  the  figure,  used  largely  by  mineralogists  to  direct 
a  lamp  or  candle  flame  upon  a  substance  to  be  heated. 


22  ENGINE-ROOM    CHEMISTRY 

Charcoal  or  strips  of  plaster  of  Paris  are  used  as  sup- 
ports for  the  substance.  When  the  blowpipe  tip  is  put 
into  the  flame  and  the  mouthpiece  blown  into,  a  long, 
hot,  pointed  flame  is  produced,  hottest  just  beyond 
the  tip  of  the  blue  cone.  This  is  known  as  the  oxidiz- 
ing flame,  because  it  oxidizes,  tarnishes,  or  burns  sub- 
stances heated  in  it.  The  oxides  or  "rusts"  of  some 
of  the  metals  coat  the  charcoal  with  characteristic 
colors.  Similarly,  when  the  blowpipe  tip  is  held  just 
outside  the  smoky  flame,  a  reducing  flame  is  produced, 
which  directed  upon  the  substance  takes  oxygen  away 
from  it  or  "reduces"  the  rusts  or  oxides  of  the  metals 
to  the  metals  themselves.  If  the  substance  contains 
sulphur,  as  a  sulphate,  by  heating  it  with  charcoal  and 
soda  in  this  flame,  a  sulphide  is  produced,  a  lump  of 
which  placed  upon  a  silver  coin  and  moistened,  gives  a 
characteristic  black  stain  of  silver  sulphide.  This  test 
can  be  used  to  test  for  sulphates  in  boiler  scales  and  for 
sulphur  in  coal. 


FIG.  8.  —  Crucible 

Crucibles.  These  (Fig.  8)  are  narrow,  deep  vessels 
of  fire-clay.  Those  made  in  Battersea,  England,  size 
C,  are  the  ones  used  in  the  Berthier  test.  They  are 
also  made  in  the  finest  Berlin  and  Meissen  porcelain: 
size  No.  7  is  the  best  adapted  for  our  work. 

Closed  Tubes  or  Matrasses.     These  are  of  hard,  that 


APPARATUS    AND    CHEMICALS  23 

is  difficultly  fusible,  glass  about  J-inch  in  diameter 
and  3  inches  long,  and  are  used  for  observing  the  be- 
havior of  substances  when  exposed  to  the  heat  of  the 
Bunsen  burner  in  the  Closed  Tube  Test  as  it  is  called. 
Drying  Ovens.  These  may  be  made  in  various  ways 
and  of  various  materials:  for  permanent  fixtures  those 
of  copper  or  metal-lined  wood  are  to  be  recommended. 
Copper  ovens  are  heated  by  gas  or  steam,  and  this 
latter  agent  is  employed  with  the  latter  type  of  oven. 
For  our  purposes  a  square  tin  or  iron  box  heated  by 
a  gas-burner  or  kerosene  stove  and  provided  with  a 
thermometer  will  serve  admirably. 


FIG.  9.  —  Porcelain  Dish 

Containing  and  Handling  Apparatus.  —  Funnels 
and  Filters.  Chemists'  funnels  are  exactly  like  the 
household  article  in  "tin"  —  tinned  iron  —  except 
that  they  are  made  of  glass  and  from  2^-3  in.  in 
diameter.  They  are  used  largely  as  supports  for  fil- 
ters. Filters  are  disks  of  unsized  paper  (filter  paper) 
three  or  four  inches  in  diameter.  They  can  be  most 
simply  folded  as  to  make  a  half-circle,  and  this  folded 
to  make  a  quarter-circle,  opened  and  placed  in  the 
funnel.  Other  methods  of  folding  are  illustrated  in 
the  books  on  analysis.  It  is  well  to  moisten  them 
with  hot  water  before  filtering  through  them. 

Porcelain  Dishes.  These  (Fig.  9),  like  the  crucibles, 
are  of  the  finest  porcelain  and  are  used  as  vessels  in 


ENGINE-ROOM    CHEMISTRY 


which  to  dissolve  substances  and  boil  them  down.  The 
Berlin  dishes  glazed  within  and  without  are  the  best; 
the  3~in.  dish  will  be  found  large  enough  for  all  pur- 
poses mentioned  here. 

Test-tubes.  Test-tubes  are  cylinders  of  thin  glass 
(Fig.  10),  sealed  round  at  the  bottom,  about  six 
inches  long  and  f  in.  in  diameter.  As  their  name 


denotes,  they  are  used  for  testing  purposes.  When 
heated  they  are  held  in  wooden  tongs  and,  like  fire- 
arms, should  never  be  pointed  toward  oneself  or  any 
one  else.  When  not  in  use  they  are  supported  in  a 
rack  or  a  block  of  wood  having  12  holes  and  six 
pegs. 

Beakers.     When    considerable    quantities"  of   liquid 
are  to  be  employed,  particularly  when  heated,  wider 


APPARATUS    AND    CHEMICALS  25 

vessels  of  thin  glass  called  beakers  (Fig.  n)  are  used, 
the  common  sizes  being  from  an  ounce  to  a  pint.    Both 


FIG.  ii.  —  Beakers 

beakers  and  test-tubes  may  be  cleaned  with  a  test-tube 
brush. 
A  wash-bottle  (Fig,  12)  is  a  very  convenient  means  of 


FIG.  12.— 
Wash-bottle 


keeping  at  hand  a  supply  of  distilled  water  from  which 
to  pour  small  quantities  when  required.     By  blowing 


26 


ENGINE-ROOM    CHEMISTRY 


into  the  mouthpiece  a  stream  of  water  is  expelled  from 
the  jet,  which  is  used  to  wash  precipitates,  etc.  The 
distilled  water  can  be  obtained  by  catching  the  con- 
densed water  from  ''returns"  and  will  be  found  pure 
enough  for  all  our  purposes.  Ordinary  tap  water  is 
too  impure  for  refined  analytical  work. 

Miscellaneous  Apparatus.  —  Iron  stands  and  rings 
(Fig.  13)  or  tripods  are  used  to  support  vessels  over  a 
lamp  for  heating.  The  apparatus  usually  rests  on 


X) 


X) 


FIG.  13.  —  Iron  Stand 

wire  gauze  upon  the  ring.  This  gauze  seems  to  pro- 
tect the  beaker  from  the  intense  heat  of  the  flame. 
When  heating  a  vessel  containing  a  liquid,  drops  of 
water  from  the  lamp  flame  are  usually  deposited  upon 
it:  as  these  are  apt  to  run  together  and  down  upon 
the  hotter  part  of  the  vessel  and  crack  it,  they  should 
be  wiped  off  from  time  to  time.  For  supporting  cru- 
cibles, iron-wire  triangles  covered  with  clay  piping  — 
pipe-stem  triangles  —  may  be  used. 


APPARATUS    AND    CHEMICALS  27 

Thermometers.  What  are  known  as  chemical  ther- 
mometers, those  with  the  divisions  of  the  scale  etched 
on  the  stem,  with  a  milk-glass  back,  are  to  be  preferred. 
They  should  be  divided  into  two  degrees  and  for  ordi- 
nary purposes  should  register  to  680  deg.  F. :  for  test- 
ing cylinder  oils  they  may  read  to  800  deg.  For  higher 
temperatures  to  1000  deg.  F.  the  "high-temperature 
thermometers/'  which  are  filled  with  carbonic  acid  or 
nitrogen  under  a  pressure  of  about  100  lb.,  may  be 
used.  These  are  usually  encased  in  a  bronze  or  iron 
tube.  For  taking  chimney  temperatures  a  thermom- 
eter should  never  be  inserted  naked  into  the  flue,  as 
a  blast  of  gas  at  a  high  temperature  may  strike  and 
burst  it :  temperatures  as  high  as  1 1 50  deg.  F.  have 
been  observed  for  a  few  moments  in  chimneys.  A 
bath  of  heavy  cylinder,  linseed  or  cottonseed  oil  con- 
tained in  a  plugged  J-in.  pipe  should  be  inserted  into 
the  flue  or  duct  and  the  thermometer  placed  in  this. 
Thermometers  should  be  tested  from  time  to  time,  and 
as  nearly  as  possible  under  the  conditions  under  which 
they  are  used,  i.e.,  with  the  same  amount  of  stem  pro- 
jecting. To  this  end  they  should  be  placed  in  a  bath 
of  melting  ice  which  practically  shows  a  temperature  of 
32  deg.  F. :  water  can  be  boiled  in  a  plugged  piece 
of  ij-in.  pipe  and  the  thermometer  suspended  in  the 
steam  —  not  dipped  into  the  water  —  when  212  deg. 
F.  should  be  indicated.  If  the  water  be  replaced  by 
naphthalene  and  the  latter  be  heated  to  boiling,  a 
temperature  of  426  deg.  F.  is  obtained  in  the  vapor. 

When  it  is  not  practicable  to  use  thermometers,  as 
with  locomotives,  the  temperature  may  be  obtained  by 


28 


ENGINE-ROOM    CHEMISTRY 


taking  the  melting-points  of  pieces  of  certain  metals, 
or  of  some  salts  contained  in  small  cast-iron  boxes 
(Fig.  14).  The  metals  and  salts  available  with  their 
melting-points  will  be  found  in  Table  VIII  of  the  Ap- 
pendix. In  the  case  of  salts  they  should  be  dried  for 
two  hours  in  the  oven  at  220  deg.  F.  For  the  meas- 
urement of  still  higher  temperatures  electrical  and 
optical  pyrometers  are  used. 


FIG.  14.  —  Melting- 
point  Boxes 

Calorimeters.  Thermometers  and  pyrometers  show 
simply  the  intensity  of  the  heat,  just  as  a  water-gage 
shows  the  pressure  on  a  service  pipe.  They  show  the 
highest  temperature  produced  by  the  combustion  of 
coal  or  gas  without  giving  any  idea  of  the  quantity  of 
heat  produced.  For  this  measurement  calorimeters 
are  employed,  just  as  a  water-meter  is  used  to  show 
the  amount  of  water  used. 

To  determine  the  heating  value  of  a  fuel  (for  which 


APPARATUS    AND    CHEMICALS  29 

specific  directions  will  be  given  in  Chapter  III)  it  is 
burned,  in  one  method,  in  a  closed  bomb,  which  is 
submerged  in  water  in  a  copper  vessel.  The  tempera- 
ture of  the  water  is  read  both  before  the  coal  is  ignited 
and  afterward,  and  the  rise  of  temperature  found. 
Knowing,  besides  this,  the  weight  of  water  and  its  spe- 
cific heat,  the  total  amount  of.  heat  generated  by  the 
fuel  can  be  determined;  and  this,  divided  by  the  weight 
of  coal  burned,  gives  the  number  of  heat  units  or  Brit- 
ish thermal  units  (B.t.u.). 

Specific  Heat.  —  This  term  has  been  used  in  the 
preceding  paragraph.  For  it,  however,  "calorific 
capacity"  could  be  substituted.  By  it  we  mean  the 
power  which  a  substance  has  of  absorbing  heat.  If 
we  place  an  ounce  of  mercury  and  an  ounce  of  water  at 
equal  distances  from  the  same  source  of  heat  and  al- 
low them  to  remain  for  the  same  length  of  time,  we  shall 
find  that  the  mercury  becomes  much  the  hotter - 
about  thirty  times  as  hot  in  fact  —  it  has  a  low  specific 
heat;  that  is,  it  takes  only  about  one-thirtieth  as  much 
heat  to  raise  the  temperature  a  given  amount  as  it 
would  to  raise  its  temperature  of  an  equal  weight  of 
water  an  equal  number  of  degrees.  Water  has  the 
greatest  specific  heat  of  any  substance,1  and  is  taken  as 
the  standard,  or  i.ooo.  The  specific  heats  of  all  other 
substances  are  therefore  expressed  in  fractions. 

That  quantity  of  heat  necessary  to  raise  the  tempera- 
ture of  one  pound  of  water  one  degree  Fahrenheit  is 
called  a  British  thermal  unit,  and  is  used  as  the  stand- 
ard unit  in  America  and  in  England.  If  we  substitute 
for  this  one  kilo  of  water  and  one  degree  Centigrade 

1  Excepting  hydrogen. 


30  ENGINE-ROOM    CHEMISTRY 

we  have  the  French  or  scientific  unit:  it  is  equal  to 
3.96  B.t.u.  On  the  other  hand,  if  a  pound  of  coal 
yield  14,500  B.t.u.,  the  number  of  calories  that  it  would 
yield  per  kilo  is  found  by  dividing  the  number  of  B.t.u. 
by  1.8,  the  equivalent  of  the  Centigrade  degree  in 
Fahrenheit  degrees;  the  English  equivalent  of  the  kilo, 
2.2  pounds,  cancels  out,  being  in  both  numerator  and 
denominator. 

Thermometer  Scales.  — The  scale  proposed  by  Fah- 
renheit in  1714  is  still  used  in  England  and  in  America: 
his  zero  was  the  lowest  temperature  then  obtainable  — 
by  ice  and  salt.  Ice  melted  at  32  of  his  degrees  above 
this,  and  water  boiled  at  180  degrees  higher.  Celsius7 
scale  started  with  the  melting-point  of  ice  as  o,  and 
the  boiling-point  of  water  as  100,  and  divided  this 
distance  into  one  hundred  equal  parts  or  degrees, 
whence  it  is  called  the  Centigrade  (loo-degree  scale). 
Thus  1 80  deg.  F.  =  100  deg.  C;  or  one  deg.  F.  =  -| 
deg.  C. ;  or  i  deg.  C.  =  -f  deg.  F.  Table  IX  in  the  Ap- 
pendix shows  the  relation  between  the  two  scales. 

Reagents.  —  Besides  these  mechanical  aids  or  tools, 
the  chemist  has  to  employ  chemical  aids,  or  "reagents," 
as  they  are  called,  because  they  bring  about  certain 
characteristic  reactions  or  tests.  Those  for  our  imme- 
diate purposes  are  not  numerous,  but  in  connection 
with  a  book  on  qualitative  analysis,  may.be  increased 
so  that  a  considerable  range  of  work  may  be  done. 

Reagents  should  be  kept  in  well-stoppered  and  cor- 
rectly labeled  bottles  of  heavy  resistant  glass,  specially 
made  to  withstand  the  wear  and  tear  of  use,  as  well  as 
the  action  of  the  chemicals  themselves.  A  size  hold- 


APPARATUS    AND    CHEMICALS  31 

ing  a  half-pint  (250  cc.)  is  most  convenient.  In  using 
them,  care  should  be  taken  never  to  lay  the  stoppers 
upon  the  desk  or  table,  as  some  dirt  may  adhere  to 
their  wet  surface  and  thereby  get  into  and  contaminate 
the  reagent.  When  they  have  been  unused  for  a  con- 
siderable time  the  crust  forming  on  the  lips  of  the  bottle 
should  be  carefully  washed  off.  In  case  the  stoppers 
stick  they  can  usually  be  started  by  gentle  tapping 
with  a  hammer.  Care  should  be  exercised  at  all  times 
to  keep  them  pure.  As  many  of  them  are  poisons,  they 
should  be  kept  under  lock  and  key,  best  in  a  wooden 
cupboard  with  a  light  in  front  of  it,  provided  with 
bronze  hinges,  hasp  and  padlock.  Iron  trimmings  and 
locks  are  more  susceptible  to  corrosion.  Care  should 
be  also  taken  to  keep  them,  and  in  general  to  perform 
experiments  in  which  they  are  used,  in  a  room  away 
from  anything  that  would  be  corroded,  rusted,  or  other- 
wise injured  by  their  fumes;  for  some  of  them  are  acid. 

The  reagents  required  for  our  work  are  comprised 
in  the  following: 

Acids.  Nitric  (HNO3),  hydrochloric  (HC1),  and 
sulphuric  (H2SO4)  acid,  all  strong  and  chemically -pure 
(C.P.),  should  be  handled  with  great  care.  In  case 
they  get  upon  the  skin  or  clothes,  they  should  be 
washed  off  at  once  with  water  and  afterward  with  a 
little  dilute  ammonia.  They  are  used  strong,  and  also 
diluted  i  part  to  4  parts  of  water,  pouring  the  acid 
into  the  water.  If  the  operation  be  reversed,  particu- 
larly with  sulphuric  acid,  explosions  may  occur  which 
will  scatter  it  about. 

Ammonium  Hydrate,   "Ammonia"   (NH4OH).     Di- 


32  ENGINE-ROOM    CHEMISTRY 

lute  the  ordinary  strong  ammonia  with  an  equal  vol- 
ume of  water  or  use  "Household  Ammonia/'  Used 
to  test  for  aluminum  (Al). 

Ammonium  Chloride  (NH4C1).  i  part  to  10  of 
water.  Place  2.5  grams  of  the  C.P.  salt  in  a  reagent 
bottle,  add  250  cc.  distilled  water  and  shake.  f  The 
exact  amount  of  water  makes  no  difference;  the  bottle 
could  be  filled  to  within  half  an  inch  of  the  top. 

Ammonium  Oxalate  (NH4)2C2O4.  I  part  to  10  of 
water,  as  above  under  ammonium  chloride.  Used  to 
test  for  lime  (Ca). 

Barium  Chloride  (BaQ2).  I  part  to  10  of  water. 
Used  to  test  for  sulphates  (R2SO4). 

Lime-water,  Calcium  Hydrate(CaO2H2).  Slake  a  small 
lump  of  quicklime  and  shake  up  the  slaked  lime  with 
water  in  a  quart  bottle  and  allow  to  stand  twenty- 
four  hours,  filtering  it  into  the  reagent  bottles  from 
time  to  time.  Used  to  test  for  carbonic  acid  (CO2). 

Potassium  Ferrocyanide.  "Yellow  prussiate  of  pot- 
ash." i  part  to  20  of  water.  Used  to  test  for  iron  (Fe). 

Silver  Nitrate  (AgNO3).  i  part  to  20  of  water. 
Used  to  test  for  chlorides  (RC1). 

Sodium  Carbonate  (Na2CO3).  C.P.  dry  powder. 
Used  to  test  for  sulphates  in  dry  way. 

Sodium  Phosphate  (Na2HPO4).  i  part  to  10  of 
water.  Used  to  test  for  magnesia  (Mg). 

Soap  Solution.  Such  a  quantity  of  white  castile 
soap  in  500  cc.  of  yo-per-cent.  alcohol  that  14.25  cc.  of 
it  gives  the  required  lather  with  50  cc.  standard  cal- 
cium chloride  solution.  This  is  equivalent  to  o.  10 
gram  of  calcium  carbonate. 


APPARATUS    AND    CHEMICALS  33 

Litmus  Paper.  For  testing  for  acids  and  alkalies. 
Acids  turn  blue  litmus  red;  alkalies,  red  litmus  blue. 
The  deep  blue  color  of  the  litmus  should  be  reduced 
by  exposure  to  the  fumes  of  hydrochloric  acid  or  with 
dilute  acetic  acid. 

Tests  for  Various  Elements  and  Compounds.  —  To 
gain  familiarity  with  the  appearance  of  the  various 
precipitates  which  are  characteristic  of  the  element 
sought,  the  experiments  described  below  may  be  per- 
formed. In  each  case  we  first  make  a  solution  con- 
taining a  compound  of  the  element  sought,  and  then 
by  suitable  means  or  reagents  throw  down  a  precipi- 
tate or  "sediment"  which  can  only  be  thrown  down 
when  the  element  in  question  is  present;  or,  instead 
of  a  precipitate,  a  color  may  be  produced. 

Test  for  Aluminum.  Dissolve  a  piece  of  common 
alum  half  as  big  as  a  pea  in  one-third  of  a  test-tube  of 
water.  Solids  dissolve  more  readily  when  powdered, 
and  when  the  water  is  warm ;  therefore  in  this  case  the 
alum  may  be  ground  in  the  mortar,  and  the  test-tube 
of  water  warmed  in  the  alcohol  or  gas-lamp  flame.  Or, 
since  alum  is  only  a  compound  of  the  metal  aluminum 
for  which  we  are  testing,  some  aluminum  filings  or 
clippings  —  that  quantity  which  could  be  retained  on 
the  tip  of  the  small  blade  of  an  ordinary  knife, 
may  be  dissolved  or  "cut"  with  hydrochloric  acid 
about  one-sixth  to  one-fourth  of  a  test-tubeful. 

Now  add  to  the  solution  in  a  fine  stream,  and  then 
drop  by  drop,  some  ammonia  water,  at  last  putting 
the  thumb  over  the  mouth  of  the  tube  and  shaking  it 
until  the  odor  of  ammonia  is  faintly  perceptible.  The 


34  ENGINE-ROOM    CHEMISTRY 

ammonia  is  now  said  to  be  "in  excess."  A  whitish 
flocculent  or  gelatinous  precipitate  appears,  which  can 
be  collected  together  on  heating  and  filtered  off  for 
closer  inspection  if  desired.  For  the  method  of  fold- 
ing the  filter  see  under  "Filters"  and  "Funnels"  on 
page  23.  The  funnel  may  be  supported  by  being  set 
into  the  test-tube  to  receive  the  filtrate.  Under  these 
circumstances  the  precipitate  (ppt.)  is  aluminum  hy- 
drate, and  when  a  precipitate  like  this  is  obtained  in 
testing  a  substance  the  composition  of  which  is  un- 
known, aluminum  can  be  said  to  be  present.  Often- 
times "confirmatory  tests"  are  used  to  substantiate 
or  confirm  these  tests,  or  to  make  sure  that  the  pre- 
cipitate formed  is  really  that  produced  by  the  element 
sought.  In  a  case  of  this  kind  some  of  the  precipitate 
on  the  filter  is  transferred,  by  means  of  a  knife-blade 
or  celluloid  paper-cutter,  to  a  piece  of  charcoal  and 
heated  in  the  oxidizing  flame  of  the  blowpipe;  it  grad- 
ually falls  to  a  white  powder,  alumina.  This  is  moist- 
ened with  a  few  drops  of  lo-per-cent.  solution  of 
nitrate  of  cobalt,  and  again  heated  before  the  blow- 
pipe. In  the  presence  of  alumina  a  fine  blue  color, 
resembling  that  seen  on  the  "blue  willow  ware"  of  our 
grandmothers,  is  produced.  The  aluminum  is  present 
in  the  solution  either  as  sulphate  (alum)  or  aluminum 
chloride  (A1C13),  made  by  dissolving  the  aluminum  in 
hydrochloric  acid. 

2A1        +  6HC1  2A1C13  +        sH2 

aluminum  +  hydrochloric  acid  =  aluminum  chloride  +  hydrogen. 

When  to  this  solution  of  aluminum  chloride,  am- 
monia water  (ammonium  hydrate)  is  added,  a  simple 


APPARATUS    AND    CHEMICALS  35 

interchange  takes  place  between  them  and  aluminum 
hydrate  (the  precipitate)  and  ammonium  chloride  are 
formed.  This  is  shown  in  the  reaction: 


A1O3H3  + 

aluminum  chloride  +  ammonium  hydrate  =  aluminum  hydrate  + 

3NH4C1 
ammonium  chloride 

That  this  reaction  would  take  place  can  be  predicted 
by  the  fact  that  a  precipitate  (aluminum  hydrate)  can 
be  formed.  We  can  foretell  with  reasonable  certainty 
that  a  reaction  will  take  place  if  either  a  precipitate 
can  be  formed  or  a  gas  liberated  under  the  conditions 
of  the  experiment. 

Test  for  Calcium  or  "Lime."  Dissolve  a  piece  of 
chalk  or  marble  as  large  as  half  a  pea,  or  the  equiva- 
lent amount  of  egg-  or  oyster-shell  in  a  teaspoonful  of 
hydrochloric  acid  (i  part  strong  acid  to  3  of  water). 
When  the  bubbling  has  ceased,  make  alkaline  with  am- 
monia. That  is,  add  ammonia  until  on  shaking  and 
blowing  out  the  vapors  in  the  tube  the  odor  of  ammonia 
persists,  that  is,  can  be  smelled  faintly.  Instead  of 
relying  on  the  sense  of  smell,  red  litmus  paper  may  be 
used.  When  a  drop  of  liquid  is  placed  by  means  of  a 
piece  of  glass  tubing  or  glass  rod  on  the  reddened  paper 
it  turns  back  to  the  blue,  and  the  liquid  is  said  to  have 
an  alkaline  reaction;  or  the  paper  may  be  dipped  into 
the  solution  to  be  tested.  After  the  solution  is  neu- 
tralized, as  this  process  of  adding  ammonia  is  called,  it 
is  filtered  into  another  test-tube  to  remove  any  undis- 
solved  chalk  or  shell  and  any  precipitate  formed  by 
the  ammonia  water;  the  filtrate  thus  obtained  is 


36  ENGINE-ROOM    CHEMISTRY 

warmed  (most  precipitates  forming  best  from  warm 
solutions),  and  ammonium  oxalate  solution  (see  "Re- 
agents") added,  when  a  copious  white  precipitate  of 
calcium  oxalate  comes  down,  which  is  evidence  of  the 
presence  of  calcium  or  "lime."  In  case  only  a  very 
small  quantity  of  calcium  was  present,  twenty-four 
hours  might  be  necessary  for  the  formation  of  the 
precipitate,  which  would  manifest  itself  by  the  ap- 
pearance of  a  faint  cloudiness  on  shaking  the  tube. 

Test  for  Magnesium.  Dissolve  ten  or  a  dozen  crystals 
-  more  or  less  —  of  Epsom  salts  in  one-fourth  of  a 
test-tube  of  water;  add  about  20  drops  of  ammonium 
chloride,  and  ammonia  water  to  fill  the  tube  nearly 
half-full  and  about  a  half-teaspoonful  sodium  phos- 
phate solution.  Exact  quantities  in  this  qualitative 
work  are  of  little  importance.  A  white  crystalline 
precipitate  of  the  double  phosphate  of  ammonium  and 
magnesium  will  appear,  gradually  increasing  in  quan- 
tity, which  may  require  twelve  hours  for  complete 
precipitation. 

Test  for  Iron.  Dip  an  iron  wire  for  a  few  seconds 
into  dilute  hydrochloric  acid,  or  dissolve  one  iron  fil- 
ing in  this  acid;  add  a  drop  of  nitric  acid  and  heat  to 
boiling,  cool,  and  add  a  few  drops  of  potassium  ferro- 
cyanide:  the  precipitate  or  color  is  ferric  ferrocyanide 
or  Prussian  blue. 

Test  for  Sulphates.  Make  a  solution  of  alum  as  in 
testing  for  aluminum;  add  a  few  drops  of  hydrochloric 
acid,  and  test  the  solution  with  litmus  paper  as  has 
already  been  explained;  now  add  some  barium  chloride 
solution  and  a  dense  white  precipitate  of  barium  sul- 


'HE 

UNIVERSITY 


AND    CHEMICALS  37 


phate  is  produced.  In  testing  for  sulphates  the  solu- 
tion must  be  always  acid,  with  nitric  or  hydrochloric 
acid;  or  else  other  acids,  as  carbonic  and  oxalic,  will 
be  precipitated  on  the  addition  of  barium  chloride. 

Test  for  Chlorides.  Make  a  solution  of  common  salt 
as  directed  for  alum;  acidify  with  pure  nitric  acid  - 
that  is,  add  a  few  drops  of  acid  —  testing  for  acid  with 
litmus  as  above,  and  add  a  few  drops  of  silver  nitrate 
solution  :  a  white  curdy  precipitate  of  silver  chloride  is 
produced.  This  turns  violet  on  exposure  to  light  and 
dissolves  in  ammonia  water. 

To  Test  for  Lime  (Calcium)  Salts  in  Boiler  Water.  — 
In  the  solutions  for  the  above  tests  there  has  been 
present  a  considerable  quantity  of  the  substance  which 
we  have  been  testing  for;  that  is,  the  solutions  have 
been  moderately  strong.  In  boiler  waters  there  may 
be  only  a  few  grains  of  solid  matter  per  gallon,  or,  as 
more  usually  expressed,  parts  per  million,  and  in  order 
to  get  a  prompt  and  characteristic  reaction  it  is  neces- 
sary to  make  a  more  concentrated  solution  by  boiling 
off  some  of  the  water.  Boil  down  in  a  porcelain  dish 
100  or  200  cc.  of  the  water  with  the  addition  of  a  few 
drops  of  pure  hydrochloric  acid,  until  about  one-tenth 
of  the  original  quantity  of  water  is  left.  Make  alka- 
line with  ammonia,  filter  and  add  ammonium  oxalate 
to  the  filtrate,  and  if  much  lime  be  present  a  pre- 
cipitate will  appear:  traces  may  require  twenty-four 
hours  for  appearance. 

To  Test  for  Sulphates  in  Boiler  Water.  —  Evaporate 
as  above,  using  an  alcohol  lamp,  as  gas  or  gasolene  con- 
tains sulphur  enough  to  vitiate  the  test,  and  filter. 


38  ENGINE-ROOM    CHEMISTRY 

Instead  of  adding  ammonia,  add  barium  chloride, 
when,  if  sulphate  be  present,  the  white  barium  sul- 
phate will  come  down :  traces  may  require  twenty-four 
hours  for  appearance. 

To  Test  Boiler  Scale. —  The  sulphates  of  aluminum, 
calcium,  etc.,  with  which  we  have  been  dealing  have 
all  been  in  solution;  and  in  case  we  had  to  deal  with  a 
solid  substance  —  for  example  a  boiler  scale  —  the 
first  thing  to.be  done  is  to  make  a  solution.  To  this 
end  the  scale  is  broken  up  fine  and  boiled  with  hydro- 
chloric acid  in  a  test-tube  or  porcelain  dish.  That 
which  does  not  dissolve  is  probably  sand.  The  solu- 
tion in  the  dish  is  evaporated  to  dryness  and  ignited  to 
render  any  dissolved  silica  or  sand  insoluble;  it  is 
treated  with  dilute  hydrochloric  acid,  which  dissolves 
everything  but  the  silica,  and  the  latter  is  filtered  off. 
The  solution  is  rendered  faintly  alkaline  with  ammonia 
when  a  reddish  brown  flocculent  precipitate  falls.  This 
is  filtered  off;  a  quantity  of  the  precipitate  equal  to 
half  a  pea  is  mixed  with  soda,  and  fused  on  a  piece  of 
platinum-foil  over  the  lamp  flame.  The  foil  is  placed 
in  a  porcelain  dish  and  boiled  with  water,  and  the  solu- 
tion filtered.  The  iron  contained  in  the  scale  is  left 
on  the  filter  as  iron  oxide;  and  any  alumina  (clayey 
material)  goes  into  solution,  by  the  fusion  with  soda. 
This  is  acidified  with  hydrochloric  acid  (that  is,  acid 
is  added  until  the  solution  reddens  litmus  paper)  and 
rendered  faintly  alkaline  with  ammonia,  when,  if  alum- 
ina be  present,  it  appears  as  a  white  flocculent  precip- 
itate. A  small  part  of  the  reddish  brown  flocculent 
precipitate  is  dissolved  in  hydrochloric  acid  by  heat- 


APPARATUS    AND    CHEMICALS  39 

ing,  diluted  with  water  and  a  few  drops  of  potassium 
ferrocyanide  added,  when  a  blue  color  or  precipitate 
of  Prussian  blue  appears,  indicating  the  presence  of 
iron. 

To  the  liquid  which  has  come  from  the  filter  contain- 
ing the  reddish  brown  precipitate,  "the  filtrate"  as  it 
is  called,  a  half-teaspoonful  of  ammonium  chloride  is 
added  and  then  ammonium  oxalate  until  no  further 
precipitation  occurs:  a  dense  white  precipitate  ap- 
pears which  is  proof  of  the  presence  of  "lime"  or  cal- 
cium. This  is  allowed  to  stand  in  a  warm  place  for  a 
day,  is  then  filtered  off,  ammonia  equal  to  about  one- 
third  the  volume  of  the  solution  being  added,  using  a 
beaker  to  hold  it  if  necessary,  and  about  a  half-tea- 
spoonful  of  sodium  phosphate  also  added.  In  case 
much  magnesia  or  magnesium  compound  is  present, 
a  crystalline  precipitate  appears.  For  small  quan- 
tities it  should  be  allowed  to  stand  over  night. 

We  have  found  by  this  analysis  all  the  bases,  iron, 
alumina,  lime  and  magnesia,  and  one  of  the  acids  — 
silicic  or  silica.  The  remainder  of  the  acids  must  now 
be  sought.  On  dissolving  a  scale  in  acid  a  bubbling 
takes  place,  and  an  odorless  gas  is  given  off.  This  gas 
is  so  heavy  that  it  can  be  poured  out  of  the  tube  into 
another  and  shaken  up  with  lime  water,  giving  a  white 
precipitate  showing  the  gas  to  be  carbonic  acid.  A 
portion  of  the  clear  liquid  is  treated  with  a  few  drops 
of  barium  chloride,  when  a  white  precipitate  of  barium 
sulphate  falls,  indicative  of  the  presence  of  a  sulphate. 
The  acids  found  are,  then,  carbonic,  silicic,  and  sul- 
phuric, and  the  scale  may  contain  calcium  carbonate 


40  ENGINE-ROOM    CHEMISTRY 

and  sulphate,  magnesium  carbonate,  clay,  aluminum 
silicate,  iron  rust,  and  possibly  sand.  The  exact  com- 
position can  be  told  only  by  a  quantitative  analysis. 
In  performing  a  qualitative  analysis  an  idea  of  the  com- 
position of  the  substance  under  examination  may  be 
obtained  by  observing  the  bulk  of  the  precipitates 
formed.  The  analysis  here  described  must  be  followed 
carefully  as  directed;  otherwise  the  conclusions  drawn 
will  be  worthless,  as  the  precipitates  obtained  will  not 
be  those  of  the  elements  mentioned. 

The  scheme  detailed  applies  only  to  substances  that 
contain  none  of  the  commonly  occurring  metals  except 
iron;  and  it  has  been  given  to  show  how  an  analysis 
is  performed.  Silver,  lead,  copper,  zinc,  tin,  etc.,  have 
not  been  considered,  as  these,  equally  with  the  reasons 
for  all  the  steps  taken  in  the  analysis  cited,  would  take 
us  beyond  the  limit  of  the  present  work.  After  com- 
pleting a  course  in  chemistry  like  that  in  Roscoe,  or 
Storer  and  Lindsay,  with  experiments,  the  subject  of 
qualitative  analysis  can  be  taken  up,  using  the  book  of 
Eliot  and  Storer,  revised  by  Lindsay,  or  that  of  A.  A. 
Noyes. 


Ill 

FUELS  AND  THEIR  ANALYSIS 

ANYTHING  that  unites  with  oxygen  with  the  evolu- 
tion of  light  and  particularly  heat  might  be  used  as  a 
fuel.  Of  these  substances  few  exist  in  sufficient  quan- 
tity or  are  sufficiently  cheap  to  be  used  as  such.  Ac- 
cording to  their  physical  condition  they  may  be  classed 
as  solid,  liquid,  and  gaseous.  The  solid  fuels  are  wood 
and  peat,  or  those  of  recent  origin;  brown,  bituminous 
and  anthracite  coal,  or  fossil  fuels;  wood  and  peat,  char- 
coal and  coke,  or  modified  fuels;  and  sawdust,  spent 
tan,  bagasse,  etc.,  or  refuse  fuels.  The  liquid  fuels  are 
crude  petroleum,  substances  derived  therefrom,  and 
various  tarry  residues  from  processes  of  distillation, 
as  "dead  oils."  The  gaseous  fuels  are  natural  gas, 
producer,  blast-furnace,  coke-oven,  and  illuminating 
gases. 

The  essential  constituents  in  all  these  are  carbon 
and  hydrogen;  the  accessory,  nitrogen,  oxygen,  water, 
and  ash;  and  the  harmful,  sulphur  and  phosphorus. 

The  amount  of  the  accessory  or  harmful  constitu- 
ents determines  the  values  of  these  materials  as  fuels; 
obviously,  those  which  contain  the  smaller  quantity  of 
these  substances  are  to  be  preferred.  In  addition  to 
this,  the  fusibility  of  the  ash  is  to  be  considered:  this 

41 


42  ENGINE-ROOM    CHEMISTRY 

should  be  as  high  as  possible  as  the  temperature  de- 
veloped, as  the  fused  ash  forms  clinkers  which  stop  up 
the  spaces  between  the  grate  bars,  rendering  the  access 
of  air  difficult  or  finally  cutting  it  off  altogether.  These 
clinkers  may  in  addition  corrode  the  grates. 

SOLID   FUELS 

Wood.  —  Considering  these  various  fuels,  we  find 
that  wood  is  mainly  woody  fiber  or  cellulose,  as  the 
chemist  calls  it.  This  is  seen  in  a  practically  pure  con- 
dition in  bleached  cloth  or  absorbent  cotton.  It  is 
formed  from  the  carbonic  acid  and  moisture  in  the  at- 
mosphere by  the  action  of  the  green  coloring  matter 
(chlorophyl)  of  plants;  carbonic  acid  +  moisture  = 
cellulose  +  oxygen.  The  plants 'absorb  the  carbonic 
acid  which  the  animals  give  off  and  furnish  the  oxygen 
necessary  for  the  sustenance  of  the  latter.  For  fuel  or 
timber,  wood  should  be  cut  when  it  contains  the  least 
sap,  that  is,  in  the  winter  when  the  sap  is  in  the  roots: 
the  percentage  of  water  in  wood  varies  from  30  per 
cent,  in  ash  to  50  per  cent,  in  poplar.  The  heavy  hard 
woods,  as  maple  and  oak,  make  the  best  fuel,  a  cord  of 
seasoned  wood  being  about  equal  to  a  ton  of  coal, 
whereas  of  the  softwoods,  as  pine  and  spruce,  double  this 
quantity  is  required.  In  a  boiler  test  the  "coal  equiva- 
lent of  kindling  wood"  used  is  usually  found  by  multi- 
plying the  weight  of  the  wood  by  0.4.  The  ash  of  wood 
is  mainly  potassium  carbonate  --  potash  or  pearlash. 

The  percentage  composition  of  wood  is  about  as 
follows: 


FUELS    AND    THEIR    ANALYSIS  43 

Water       Carbon       Hydrogen       Oxygen       Ash       Sp.  Gr. 
20  39  4.4  35.6  i  0.5 

When  burned  it  evolves  from  7000  to  9000  B.t.u.  per 
pound  and  requires  about  6  pounds,  or  74.1  cubic  feet, 
of  air  for  its  combustion. 

Peat  is  the  compacted  roots  and  stems  of  certain  marsh 
plants,  more  particularly  the  mosses,  which  have  under- 
gone a  slow  decay  under  water.  The  process  is  sup- 
posed to  resemble  the  first  stage  of  the  production  of 
coal,  marsh  gas  (methane)  and  carbonic  acid  being 
evolved. 

It  contains  10  per  cent,  of  moisture  even  when  "thor- 
oughly dry'"';  this  may  vary  from  20  to  50  per  cent,  in 
air-dried  specimens.  Nearly  one-third  of  the  available 
heat  is  employed  in  driving  off  this  moisture.  Its  fuel 
value  is  further  diminished  by  the  high  content  of  ash, 
which  varies  from  3  to  30  per  cent.,  averaging  15  per 
cent. 

In  its  natural  condition,  peat  finds  little  use  as  a  fuel 
in  this  country;  it  is,  however,  shredded  and  washed, 
whereby  much  of  the  sand  and  earth  is  separated. 
Oftentimes  the  peat  is  sufficiently  free  from  mineral 
matter  so  that  the  washing  may  be  omitted. 
It  is  then  compressed  into  cylindrical  blocks  about 
two  inches  in  diameter  which  are  used  for  do- 
mestic purposes  and  are  particularly  well  adapted 
for  conditions  where  a  fuel  free  from  sulphur  and 
phosphorus  is  essential.  In  Sweden  alone  two  million 
tons  of  peat  briquets  are  used  yearly.  In  Russia  peat 
impregnated  with  petroleum  residuum,  "petrolized 
peat,"  is  used. 


44  ENGINE-ROOM    CHEMISTRY 

The  percentage  composition  of  peat  is  approximately: 

Water  Carbon  Hydrogen  Oxygen  Nitrogen  Ash  Sp.  Gr. 
German     16.4        41.0  4.3  23.8  2.6        11.9     1.05  1 

American  20.8        40.8  4.4  26.6  7.7 

The  heating  value  is  about  the  same  as  wood,  and  prac- 
tically the  same  amount  of  air  is  required  for  its  com- 
bustion. The  heating  value  of  the  compressed  peat, 
or  peat  briquets  (or  .brikettes),  is  not  far  from  8400 
B.t.u.  per  pound,  or  about  60  per  cent,  that  of  ordinary 
soft  coal. 

Coal.  —  Geologists  tell  us  that  coal  was  probably 
produced  by  the  decay  under  fresh  water  of  plants  be- 
longing principally  to  the  Conifer,  Fern  and  Palm  fam- 
ilies; these  flourished  during  the  Carboniferous  Age  to 
an  extent  which  they  never  approached  before  or 
since.  Representatives  of  the  last  family,  which  it  is 
thought  produced  most  of  the  coal,  have  been  found 
2  to  4  feet  in  diameter  and  80  feet  in  hight. 

By  their  decay,  carbon  dioxide,  "choke-damp," 
marsh-gas,  "fire-damp,"  and  water  were  evolved.  The 
change  might  be  represented  by  the  equation 


6C6Hi0O5  = 

Cellulose  Bituminous  Coal 

Some  idea  of  the  density  of  the  vegetation  and  the 
time  required  may  be  obtained  from  the  fact  that  it  has 
been  calculated  that  100  tons  of  vegetable  matter  — 
the  amount  produced  per  acre  per  century  —  if  com- 
pressed to  the  specific  gravity  of  coal  and  spread  over 
an  acre  would  give  a  layer  less  than  0.6  of  an  inch 

1  Taken  from  Gill,  "Gas  and  Fuel  Analysis  for  Engineers,"  by  permission  of  the 
publishers,  John  Wiley  &  Sons,  New  York. 


FUELS    AND    THEIR    ANALYSIS  45 

thick.  Now  four-fifths  of  this  is  lost  in  the  evolution 
of  the  gaseous  products,  giving  as  a  result  an  accumu- 
lation of  one-eighth  of  an  inch  per  century,  or  one  foot  in 
10,000  years.1 

Brown  Coal  or  Lignite  may  be  regarded  as  forming 
the  link  between  wood  and  coal;  geologically  speak- 
ing it  is  of  later  date  than  the  true  coal.  Most  of  the 
coal  west  of  the  Rocky  Mountains  is  of  this  variety. 

As  its  name  denotes,  it  generally  is  of  brown  color  — 
although  the  western  coal  is  black  —  and  has  a  con- 
choidal  fracture.  It  contains  a  large  quantity  of 
water  when  first  mined,  as  much  as  60  per  cent.,  and 
when  "air-dry"  from  15  to  20  per  cent.  The  percent- 
age of  ash  is  also  high,  from  i  to  20  per  cent. 

The  percentage  composition  of  brown  coal  may  be 
considered- as  approximately: 

Water  Carbon  Hydrogen  Oxygen  and  Nitrogen  Ash  Sp.  Gr. 
German  18.0       50.9  4.6  16.3  10.2        1.3 

Bituminous  Coal.  This  is  the  variety  from  which  all 
the  following  coals  are  supposed  to  have  been  formed, 
by  a  process  of  natural  distillation  combined  with  pres- 
sure. According  to  the  completeness  of  this  process 
we  have  specimens  which  contain  widely  differing 
quantities  of  volatile  matter.  This  forms  the  true  basis 
for  the  distinguishing  of  the  varieties  of  coal.  In  or- 
dinary bituminous  coal  this  volatile  matter  amounts 
to  30  or  40  per  cent.  Three  varieties  of  bituminous 
coal  are  ordinarily  distinguished,  as  follows: 

1  In  case  the  reader  desires  to  follow  in  a  more  extended  manner  the  geology  of 
coal,  reference  may  be  had  to  Le  Conte's  "  Elements  of  Geology,"  pages  345-414,  3d 
ed. 


46  ENGINE-ROOM    CHEMISTRY 

Dry  or  non-caking  —  those  which  burn  freely  with 
but  little  smoke  and,  as  the  name  denotes,  do  not  cake 
together  when  burned.  The  coals  from  Wyoming  are 
examples  of  this  class. 

Caking  —  those  which  produce  some  smoke,  and 
cake  or  sinter  together  in  the  furnace.  Examples  of 
these  are  the  New  River  and  Connellsville  coals. 

Fat  or  long-flaming  —  those  producing  much  flame 
and  smoke  and  which  do  or  do  not  cake  in  burning; 
volatile  matter  50  per  cent,  or  more.  Some  of  the 
Nova  Scotia  coals  belong  to  this  class. 

Bituminous  coal  varies  much  in  its  composition,  is 
black  or  brownish  black,  soft,  friable,  lustrous,  and  of 
specific  gravity  of  1.25  to  1.5.  Moisture  varies  from 
0.25  to  8  per  cent.,  averaging  about  5. 

The  percentage  composition  of  bituminous  coal  may- 
be considered  as  approximately: * 

Water      Carbon      Hydrogen      Oxygen      Nitrogen      Ash      Sulphur 
0.9  77.1  5.2  6.7  1.6  7.6  1.0 

Water    Volatile  Matter     Fixed  Carbon     Ash 
0.9  27.4  64.1  7.6 

Semi-Bituminous  or  Semi- Anthracite  Coal  is  upon 
the  border-line  between  the  preceding  and  the  follow- 
ing variety;  it  is  harder  than  bituminous,  contains  less 
volatile  matter  (15  to  20  per  cent.),  and  burns  with  a 
shorter  flame.  An  example  of  this  is  the  Pocahontas  coal. 

The  percentage  composition  of  semi-bituminous  and 
semi-anthracite  coal  may  be  considered  to  be  approxi- 
mately: 1 

1  H.  J.  Williams. 


FUELS    AND    THEIR    ANALYSIS  47 

Water     Carbon     Hydrogen     Oxygen     Nitrogen     Ash     Sulphur 

0.5          83.0  4.7  4-2  1.3  5-5          °-8 

Water        Volatile  Matter         Fixed  Carbon         Ash 

o-5  l6-7  77-3  5-5 

Anthracite  Coal  is  the  hardest,  most  lustrous,  and 
densest  of  all  the  varieties  of  coal,  having  a  specific 
gravity  of  1.3  to  1.75;  it  contains  the  most  carbon  and 
least  hydrogen  and  volatile  matter  (5  to  10  per  cent.)- 
It  has  a  vitreous  fracture  and  kindles  with  difficulty, 
burning  with  a  feeble  flame,  giving  little  or  no  smoke 
and  an  intense  fire.  The  Lehigh  coal  is  an  excellent 
example  of  this  class. 

The  percentage  composition  of  anthracite  coal  may 
be  considered  as  approximately: 1 

Water      Carbon      Hydrogen      Oxygen      Nitrogen      Ash      Sulphur 
2.0  83.9  2.7  2.8  0.8  7.2  0.6 

Water        Volatile  Matter         Fixed  Carbon         Ash 
2.0  4.3  86.5  7.2 

The  ash  of  coal  varies  from  i  to  20  per  cent.,  and  is 
mainly  clay  —  silicate  of  aluminum  —  with  traces  of 
lime,  magnesia,  and  iron.  When  coal  is  burned  it 
yields  from  10,980  to  14,400  B.t.u.  and  requires  about 
twelve  times  its  weight  of  air,  or  156.7  feet  per  pound. 
For  the  greatest  economy  Scheurer-Kestner  found  that 
this  should  be  increased  from  50  to  100  per  cent. 

The  sizes  of  anthracite  coal  that  are  usually  found 
on  the  market  are: 

Broken  or  furnace,  that  retained  by  a  screen  with 
meshes  2j  inches  apart. 

1  H.  J.  Williams. 


48  ENGINE-ROOM    CHEMISTRY 

Egg,  that  retained  by  if -in.  mesh,  passing  2%-in. 

Stove,  that  retained  by  i^-in.  mesh,  passing   if -in. 

Nut,  that  retained  by  f-in.  mesh,  passing  i^-m- 

Pea,  that  retained  by  |-in.  mesh,  passing  J-in. 

Buckwheat,  rice,  barley,  and  culm  are  smaller  sizes 
than  £-in.  It  is  worthy  of  note  that  the  smaller  the  coal 
the  higher  the  percentage  of  ash,  that  in  buckwheat 
being  about  16  per  cent,  as  against  5  per  cent,  in  egg. 

Coke  is  prepared  by  the  distillation  of  bituminous 
coal  in  ovens.  These  are  of  two  types:  those  in  which 


FIG.  15.—  Otto-Hoffman  Coke  Oven. 
Longitudinal  Section 

the  distillation  products  are  allowed  to  escape,  the 
"beehive"  ovens;  and  those  in  which  they  are  carefully 
saved,  as  the  Otto-Hoffman,  Semet-Solvay,  Simon- 
Carves  and  others.  The  "beehive"  ovens  yield  from 
50  to  65  per  cent,  of  the  weight  of  the  coal  used,  about 
2j  tons.  The  Otto-Hoffman  ovens,  shown  in  longitudi- 
nal section,  Fig.  15,  in- cross  section,  Fig.  16,  and  gen- 
eral perspective,  Fig.  17,  are  long,  narrow,  thin-walled 
retorts  33  x  6  x  1.5  feet,  regeneratively  heated  by  side 
and  bottom  flues.  The  regenerative  heating  consists 


FUELS    AND    THEIR    ANALYSIS 


49 


in  allowing  the  products  of  combustion  to  heat  to  a 
good  red  heat  the  chambers  through  which  the  gas  and 


FIG.  1  6.  —  Otto-Hoffman 
Coke  Oven.     Cross  Section 


the  air  for  its  combustion  pass.    Two  sets  of  these 
chambers  are  used  alternately,  usually  half-hourly,  one 


FIG    17. —  Otto-Hoffman  Coke  Oven. 
General  Perspective 

being  heated  by  the  products  of  combustion,  while  the 
gas  and  the  air  are  being  heated  by  the  other  set.     Six 


50  ENGINE-ROOM    CHEMISTRY 

tons  of  coal  make  the  charge,  and  the  yields  of  by- 
products are  about  as  follows:  Coke,  70  to  75;  gas, 
16  (10,000  cubic  feet);  tar,  3.3;  ammonia,  0.3  to  1.4 
per  cent. 

The  Semet-Solvay  ovens  differ  from  the  Otto-Hoff- 
man in  that  their  walls  are  thicker,  serving  to  store  up 
the  heat.  They  also  cost  less  for  repairs  and  in  leak- 
age, and  are  not  regeneratively  heated;  the  yield  of 
coke  is  higher,  about  80  per  cent.  Fig.  18  shows  a 
cross  section  of  the  oven. 


FIG.  18.  —  Semet-Solvay  Coke  Oven 

The  analysis  of  Connellsville  coke,  with  the  coal 
from  which  it  is  prepared,  is  as  follows: 

Water    Vol.  Matter     Carbon     Sulphur  Ash 

Coal 1.3  30.1  59.6  0.8  8.2 

Coke 0.03  1.3  89.2  0.084  9-5 

Fixed  Carbon 

Otto-Hoffman  Coke.  .    3.7  1.3  86.1  8.9 

Heating  value  12,800  B.t.u. 

The  Minor  Solid  Fuels.  —  As  was  said  in  the  early 
part  of  this  chapter,  the  efficiency  of  fuel,  and  particu- 
larly of  the  minor  solid  fuels,  depends  upon  the  amount 


FUELS    AND    THEIR    ANALYSIS  51 

of  moisture  which  they  contain.  Sawdust  and  Log- 
wood chips  are  employed  as  fuel  to  good  advantage 
in  special  automatic  furnaces;  spent  tan  bark  with  57 
per  cent,  moisture  gave  an  evaporation  of  4  pounds 
of  water  per  pound  of  bark. 

Wlaeat  straw  finds  application  as  a  fuel  in  agricul- 
tural districts,  .3^  pounds  being  equal  to  one  pound  of 
coal.  Upon  sugar  plantations  the  crushed  cane  or 
bagasse,  partially  dried,  is  extensively  used  as  a  fuel. 
With  1 6  per  cent,  of  moisture  it  gave  an  evaporation 
of  double  its  weight  of  water. 

Briquets,  "Patent  Fuel."  In  Europe  coal  dust  is 
cemented  together  with  some  tarry  binding  material, 
baked  or  compressed  into  blocks  usually  about  6x2 x  i 
inch,  and  used  as  a  fuel.  In  some  cases  they  take  the 
form  and  size  of  a  large  goose  egg,  and  are  called 
eggettes.1 

STORAGE    OF    COAL     AND    SPONTANEOUS     COMBUSTION 

While  authorities  differ  as  to  the  way  and  manner  in 
which  coal  should  be  stored,  as  regards  hight  of  pile, 
number,  size  and  arrangement  of  ventilating  channels, 
they  are  practically  agreed  that  it  should  always  be 
covered.  Six  months'  exposure  to  the  weather  may 
cause  a  loss  of  from  10  to  40  per  cent,  in  heating  value. 
The  North  German  Lloyd  Steamship  Company  stores 
its  coal  in  a  covered  bin  provided  with  ventilators, 
and  restricts  the  hight  of  the  pile  to  8  feet.  A  large 
gas  company  in  a  Western  city  also  uses  a  covered  bin, 

1  These  are  now  being  made  at  Scranton,  Pa.- 


52  ENGINE-ROOM    CHEMISTRY 

with  ventilators  8  inches  square  every  20  feet ;  the  night 
of  the  pile  may  be  from  10  to  15  feet.1  Ventilating 
flues  serve  the  additional  purposes  of  enabling  the 
temperature  of  the  pile  to  be  ascertained  before  igni- 
tion sets  in,  and  as  a  means  of  introduction  of  either 
steam  or  carbonic  acid  to  extinguish  any  fire  which 
may  occur.  All  the  supports  of  the  bin  in  contact 
with  the  coal  should  be  of  brick  or  iron,  and  if  of  hol- 
low iron,  filled  with  cement. 

The  spontaneous  combustion  of  coal  is  due  primarily 
to  the  rapid  absorption  of  oxygen  by  the  finely  divided 
coal  and  to  the  oxidation  of  iron  pyrites,  "coal  brasses," 
occurring  in  the  coal.  The  conditions  favorable  to 
this  process  are:  first,  a  supply  of  air  sufficient  to  fur- 
nish oxygen,  but  of  insufficient  volume  to  carry 
off  the  heat  generated;  second,  finely  divided 
coal,  presenting  a  large  surface  for  the  absorption 
of  oxygen;  third,  a  considerable  percentage  of 
volatile  matter  in  the  coal;  and  fourth,  a  high  ex- 
ternal temperature. 

A  good  way  to  extinguish  a  fire  in  a  coal  pile  not 
provided  with  ventilators  consists  in  removing  and 
spreading  out  the  coal  and  flooding  the  burning  part 
with  water.  Another  method  consists  in  driving  a 
number  of  iron  or  steel  pipes  provided  with  "driven 
well  points"  at  the  place  where  combustion  is  taking 
place,  and  through  these  forcing  water  or  steam  upon 
the  fire. 


1  A  large  electric  company  in  that  same  city  has  arranged  to  store  14,000  tons 
of  coal  under  water  in  12  pits.  A  steam  shovel  is  used  to  dig  out  the  coal. 
(Engineering  and  Mining  Journal,  September  15,  1906.) 


FUELS    AND    THEIR    ANALYSIS 


53 


The  table  shows  the  composition  and  heating  value 
of  some  American  coals : 

PROXIMATE  ANALYSIS  AND  HEATING  VALUE  OF 
AMERICAN  COALS  x 


• 

Heat 

Name 

Moist- 
ure 

Vol. 
Matter 

Fixed 
Carbon 

Ash 

Sulphur 

Value 
per  Ib. 

B.t.u. 

ANTHRACITE  : 

Northern  field 

3-4 

4.4 

83-3 

8.2 

0.7 

13160 

SEMI-ANTHRACITE  : 

Loyalsock 

!-3 

8.1 

83.3 

6.2 

1.6 

13920 

SEMI-BITUMINOUS  : 

Clearfield,  Pa. 

0.8 

22.5 

71.8 

4.0 

0.9 

1495° 

Pocahontas,  Va. 

I.O 

21.0 

744 

3-o 

0.6 

15070 

New   River,  W. 

0.8 

17.9 

77.6 

3-4 

°-3 

15220 

Va. 

BITUMINOUS: 

Connellsville,Pa 

J-3 

30.1 

59  -6 

8.2 

0.8 

14050 

Pittsburg,  Pa. 

1.4 

35-9 

52.2 

8.0 

1.8 

13410 

Hocking  Valley, 

6.6 

35-0 

48.9 

8.0 

1.6 

12130 

Ohio 

Missouri 

6.4 

37-6 

47-9 

8.0 

— 

12230 

LIGNITES: 

Iowa 

8.4 

37-i 

35-6 

18.9 

— 

8720 

Utah 

9-3 

42.0 

44-4 

3-2 

1.2 

11030 

1  Taken  from  "  Steam,"  published  by  the  Babcock  &  Wilcox  Co. 


54  ENGINE-ROOM    CHEMISTRY 

ANALYSIS   OF   SOLID    FUELS 

Sampling.1  In  sampling  from  cars  proceed  as  fol- 
lows: Beginning  at  one  corner  of  the  car,  drive  a 
scoop  shovel  vertically  down  as  deep  as  it  will  reach. 
Bring  it  out  with  all  the  coal  it  will  hold  and  throw  it 
into  a  cart  or  wheelbarrow.  Repeat,  taking  six  scoop- 
fuls  along  one  side  of  the  car,  at  equal  intervals,  six 
through  the  center  and  six  along  the  other  side.  Place 
the  coal  taken,  on  a  close  tight  floor,  and  break  all  the 
lumps  larger  than  an  orange.  Mix  by  shoveling  it 
over  on  itself,  back  and  forth,  quarter  and  reject  oppo- 
site quarters.  Break  finer,  as  may  be  necessary,  and 
continue  to  quarter  down  until  a  sample  is  obtained 
small  enough  to  go  into  a  quart  fruit  jar  and  having 
no  larger  than  J-in.  cube.  The  sample  may,  with 
advantage,  be  run  rapidly  through  a  mill  which 
will  break  it  into  the  size  mentioned.  Transfer  it  to 
the  jar  and  make  sure  the  latter  is  sealed  air-tight  be- 
fore it  is  set  aside.  All  of  these  operations  should  be 
conducted  as  rapidly  as  possible,  to  guard  against  any 
change  in  the  moisture  content  of  the  coal. 

Possibly  a  more  representative  sample  may  be  ob- 
tained by  taking  shovelfuls  of  the  coal  at  regular  in- 
tervals during  the  loading  or  unloading  of  the  car.  In 
boiler  tests  shovelfuls  of  coal  should  be  taken  at  reg- 
ular intervals  and  put  into  a  tightly  covered  barrel  or 
receptacle  and  placed  where  it  is  protected  from  the 
heat  of  the  furnace.  In  sampling,  two  conditions 
must  be  rigidly  observed:  first,  the  original  sample 

1  From  the  report  of  the  Committee  on  Coal  Analysis,  Journal  American  Chem- 
ical Society,  xxi  (1899),  1116. 


FUELS    AND    THEIR   ANALYSIS  55 

should  be  of  considerable  size  and  thoroughly  represent- 
ative; and  second,  the  quartering  down  to  an  amount 
which  can  be  put  into  a  sealed  jar  should  be  carried 
out  as  quickly  as  possible  after  the  sample  is  taken. 
Shipment  in  wooden  receptacles  should  not  take  place 
with  coals  containing  more  than  2  per  cent,  of  moisture. 

For  the  analysis,  quarter  dawn  the  sample  in  the  jar 
further  to  about  3  ounces  —  a  good  handful;  run  this 
quickly  through  a  coffee  mill  set  to  grind  as  finely  as 
possible,  and  transfer  a  portion  of  this  to  a  tightly 
stoppered  test-tube  for  use  in  determining  moisture. 
Grind  about  half  an  ounce  of  the  remainder  moderately 
fine  in  a  porcelain  or  iron  mortar,  transfer  to  a  tightly 
corked  tube  for  use  in  other  determinations.  Careful 
samplings  and  careful  treatment  of  samples  are  neces- 
sary to  obtain  reliable  results,  especially  in  the  deter- 
mination of  moisture.  A  car-load  of  many  Western 
coals  may  lose  several  hundred  pounds  of  moisture 
daily  while  standing  on  the  track,  and  the  same  coal 
may  lose  several  per  cent,  of  moisture  by  standing  for 
a  few  days  or  weeks  in  a  loosely  stoppered  bottle. 

The  methods  employed  in  the  analysis  of  fuels  are 
largely  a  matter  of  convention,  various  methods  giving 
varied  results;  for  example,  it  is  well-nigh  impossible 
to  obtain  accurately  the  percentage  of  moisture  in  coal, 
as  when  heated  sufficiently  hot  to  expel  all  the  moist- 
ure, some  of  the  hydrocarbons  are  volatilized. 

Moisture.  Conventional  method:  Dry  one  gram  of 
coal  in  an  open  crucible  at  220  to  225  deg.  F.  (104  to 
107  deg.  C.)  for  one  hour. 

Another   method:  Procure    a   pair   of   3~in.    watch 


56  ENGINE-ROOM    CHEMISTRY 

glasses,  the  edges  of  which  are  ground  to  fit  accurately 
together  and  which  are  held  together  by  a  watch-glass 
clip.  Weigh  out  about  5  grams  of  the  coal  from  the 
test-tube  mentioned  above,  between  these  glasses, 
using  the  horn  pan  balances. 

Remove  the  clip,  open  the  glasses  and  place  them  in 
the  oven  at  220  to  225  deg.  F.  (104  to  107  deg.  C.)  for 
one  hour;  remove  them  from  the  oven,  replace  the 
clip,  cool  under  a  bell  jar  and  weigh  them  cold.  The 
loss  of  weight  represents  the  moisture  in  the  coal  and 
should  be  expressed  in  per  cent. 

The  conventional  method  of  drying  one  gram  of  coal 
in  an  open  crucible  at  the  above  temperature  cannot 
be  used  unless  an  analytical  balance  sensitive  to  milli- 
grams is  at  hand.  The  method  outlined  gives  results 
closely  agreeing  with  the  latter. 

Volatile  Combustible  Matter,  Coke,  and  A  si.  These 
determinations  cannot  be  carried  out  with  sufficient 
accuracy  using  the  horn  pan  balances;  also  a  gas-burner 
for  heating  the  coal  is  essential. 

The  method  consists  in  heating  one  gram  of  coal  with 
a  flame  of  definite  size  for  a  definite  length  of  time  in 
a  platinum  crucible.1  Professor  Parr 2  recommends  a 
porcelain  crucible  in  a  special  furnace. 

These  are  all  the  determinations  that  it  is  possible 
to  perform  with  the  apparatus  at  hand  and  without 
careful  training  and  considerable  experience  in  the 
handling  of  delicate  apparatus.  The  other  determina- 
tions involved  will  be  briefly  described. 

1  Gill,  "  Gas  and  Fuel  Analysis  for  Engineers." 

2  Parr,  "The  Coals  of  Illinois."     University  of  Illinois  Bulletin,  vol.  i,  No.  20. 


FUELS    AND    THEIR    ANALYSIS  57 

Carbon  and  Hydrogen.  Carbon  exists  in  coal  prob- 
ably in  the  free  condition  and  also  combined  with  hy- 
drogen. These  elements  are  determined  by  burning 
the  coal  in  a  stream  of  air  or  oxygen  freed  from  car- 
bonic acid  and  moisture;  the  carbon  burns  to  carbonic 
acid  and  the  hydrogen  to  water,  both  of  which  are 
absorbed  in  suitable  chemicals  contained  in  weighed 
tubes  and  bulbs.  From  their  increase  in  weight  the 
weights  of  these  gaseous  products  are  found,  from 
which  the  weights  of  carbon  and  hydrogen  can  be  ob- 
tained and  the  percentages  of  these  constituents  calcu- 
lated. Parr  '  dissolves  in  water,  in  a  flask,  the  residue 
from  the  determination  of  heating  power  in  his  calori- 
meter, acidifies,  liberating  the  carbonic  acid,  and  meas- 
ures it,  from  which  he  can  determine  the  total  carbon 
in  the  coal. 

Nitrogen  is  determined  by  Kjeldahl's  method,  by 
which  the  nitrogeneous  bodies  in  coal  are  changed  to  am- 
monia by  digestion  with  strong  sulphuric  acid  and  potas- 
sium permanganate.  By  distilling  the  residue  treated 
with  soda,  the  ammonia  is  liberated,  caught  in  acid  of 
definite  strength,  and  thus  its  quantity  determined. 

Sulphur  is  estimated  by  heating  the  coal  with  a  mix- 
ture of  magnesia  and  soda,  cooling,  and  burning  the 
coal  by  igniting  with  ammonium  nitrate.  The  result- 
ing mass  is  dissolved  in  hydrochloric  acid  and  the  sul- 
phuric acid,  into  which  the  sulphur  compounds  in  the 
coal  have  been  changed,  estimated  by  precipitation 
with  barium  chloride  in  the  usual  way.  Parr1  uses 
the  residue  from  the  combustion  in  his  calorimeter 

1  Parr,  "  The  Coals  of  Illinois."    University  of  Illinois  Bulletin,  vol.  i,  No.  20. 


58  ENGINE-ROOM    CHEMISTRY 

for  the  determination  of  sulphur.  Instead  of  weighing 
the  barium  sulphate  precipitated,  it  is  estimated  photo- 
metrically. 

Oxygen  is  determined  by  adding  the  percentage  of 
carbon,  hydrogen,  ash,  nitrogen,  sulphur,  and  moisture 
together  and  subtracting  their  sum  from  100;  there  is 
no  method  for  its  direct  determination. 


FIG.  19. —  William  Thomson's  Calori- 
meter 


DETERMINATION    OF    THE    CALORIFIC     POWER    OF    SOLID 
AND    LIQUID    FUEL 

A.  Direct  Methods.  — Many  forms  of  apparatus  have 
been  proposed  for  this  purpose.  With  the  exception 
of  those  employing  Berthelot's  principle  —  of  burning 
the  substance  in  a  bomb  under  a  high  pressure  of  oxy- 
gen —  few  have  yielded  satisfactory  results. 

William  Thomson's   (Fig.    19)   and  Barms' s  calori- 


FUELS    AND    THEIR    ANALYSIS 


59 


meter  (Fig.  20),  in  which  the  coal  is  burned  in  a  bell 
jar  of  oxygen,  usually  yield  results  as  much  as  3  per 
cent,  from  the  real  value,  obtained  by  the  Mahler 
bomb,  and  they  may  be  8  per  cent,  from  the  truth. 


1 


FIG.  20.  —  Barrus's  Calori- 
meter 

Furthermore,  it  is  not  easy  to  burn  certain  anthracite 
and  semi-bituminous  coals  in  this  type  of  apparatus. 
Lewis  Thompson's  calorimeter  (Fig.  21),  in  which  the 
coal  is  burnt  in  a  bell  jar  by  oxygen  furnished  by  the 
decomposition  of  potassium  chlorate  or  nitrate,  gives 
results  which  must  be  increased  by  about  15  per 
cent. 


6o 


ENGINE-ROOM    CHEMISTRY 


Parr's  calorimeter  (Fig.  22)  employs  the  same  prin- 
ciple as  the  preceding,  but  possesses  the  advantage 
that  no  gases  are  evolved  from  it  as  in  all  the  foregoing 
forms,  which  carry  off  heat  in  bubbling  through  the 
water.  It  gives  results  well  within  0.5  per  cent,  of 
those  obtained  by  the  bomb  calorimeter.  In  two 
cases  which  have  come  to  the  writer's  notice  it  has  ex- 


FIG.  21.  —  Lewis  Thompson's  Calorimeter 

ploded,  scattering  hot  sodium  peroxide  about,  causing 
painful  and  in  one  case  serious  burns. 

Berthelot's,  Mahler's,  Williams  s,  or  Norton's  calori- 
meter (Fig.  23),  is  of  the  bomb  type,  constructed  of 
mild  steel  or  phosphor  bronze  and  lined  with  platinum, 
enamel,  or  gold.  The  coal  is  burned  under  a  pressure 
of  225  to  250  pounds  of  oxygen  in  this  closed  vessel 
provided  with  an  electrical  ignition.  It  gives  results 


FUELS    AND    THEIR    ANALYSIS 


6l 


which  with  proper  corrections  are  accurate,  as  all  of  the 
heat  developed  by  the  fuel  is  measured  and  the  losses 
can  be  exactly  determined. 

All  these  apparatus  are  expensive  and  require  ex- 
perience in  manipulation,  and  with  the  exception  of 


FIG.  22.  —  Parr's  Calorimeter 

the  last  two  types  give  results  no  more  nearly  correct 
than  the  one  about  to  be  described.1 

Beribiers  Method.  This  uses  as  a  measure  of  the 
heating  value  the  amount  of  lead  which  a  fuel  will  re- 
duce from  the  oxide;  that  is  to  say,  the  heating  value 
is  proportional  to  the  amount  of  lead  reduced  or  oxy- 
gen absorbed. 

1  Directions  for  their  use  as  well  as  a  more  detailed  description  will  be  found  in 
"Gas  and  Fuel  Analysis  for  Engineers"  ;  also  Poole's  "Calorific  Power  of  Fuels." 


62 


ENGINE-ROOM    CHEMISTRY 


One  gram  of  the  finely  powdered  dry  coal  is  carefully 
weighed  out  on  the  horn  pan  scales  and  intimately 
mixed  with  60  grams  of  common  litharge  (oxide  of 
lead)  and  10  grams  of  ground  glass.  This  mixing  can 
be  done  with  a  palette  knife  on  a  sheet  of  glazed  paper. 
The  mixture  is  transferred  to  a  clay  crucible  of  the  size 
of  Battersea  C,  covered  with  a  layer  of  salt,  the  crucible 


FIG.  23.  —  Norton's  Calorimeter 

covered  and  heated  to  redness  in  the  hottest  part  of  the 
boiler  furnace  for  fifteen  to  twenty  minutes.  The  crucible 
is  cooled,  then  broken,  the  lead  button  carefully  cleansed 
from  the  adhering  slag  and  weighed  on  the  scales. 

The  number  of  grams  of  lead  obtained,  reduced  to 
the  basis  of  that  obtained  from  one  gram  of  coal,  in 
case  exactly  one  gram  of  coal  was  not  used,  multiplied 


FUELS    AND    THEIR    ANALYSIS  63 

by  483  gives  the  number  of  B.t.u.  that  will  be  yielded 
by  one  pound  of  coal.  An  example  will  make  this 
clear. 

Weight  of  coal  taken,  1.04  grams. 

Weight  of  lead  button,  31.84  grams. 

31.84  -T-  1.04  =  30.62,  X  483   =  i4,75o  B.t.u. 

Two  other  experiments  gave  14,500  and  14,550 
B.t.u.  The  same  coal  gave  in  the  Mahler-Norton 
bomb,  14,200  B.t.u.,  or  2.8  per  cent,  lower,  which 
it  will  be  observed  is  as  close  as  any  calorimeter 
gives,  excepting  Parr's. 

B.  By  Calculation. — In  case  the  chemical  analysis 
of  the  coal  be  given,  its  heating  value  can  be  found 
by  calculation.  This  depends  upon  the  principle  that 
the  heating  value  of  a  substance  is  the  sum  of  the 
heating  values  of  its  constituents.  If  we  could  deter- 
mine the  heating  value  of  the  carbon  and  hydrogen 
contained  in  the  coal,  these  values  multiplied  by  the 
percentage  of  these  elements  in  the  coal  would  give 
the  heating  value.  As  we  have  but  a  faint  idea  of  the 
way  in  which  carbon  and  hydrogen  occur  in  coal,  their 
exact  heating  values  cannot  be  determined,  and  in 
their  stead  the  values  obtained  by  burning  charcoal 
and  pure  hydrogen  are  employed.  Inasmuch  as 
hydrogen  combines  with  eight  times  its  weight  of 
oxygen,  the  oxygen  in  the  coal  is  considered  to  ren- 
der inert  the  hydrogen  in  the  coal  corresponding  to 
eight  times  the  weight  of  oxygen,  and  this  is  sub- 
tracted from  the  percentage  of  hydrogen,  giving  the 
percentage  of  hydrogen  actually  available  as  fuel. 

The  following  formula  is  found  to  give  results  in 


64  ENGINE-ROOM    CHEMISTRY 

B.t.u.  within  about  3  per  cent,  of  those  obtained  in 
the  bomb  calorimeter: 

I4540C  +  51840  (h  —  f )  —  io8ow 
100 

In  case  the  percentage  of  sulphur  exceeds  2,  this 
should  be  taken  into  consideration,  by  the  introduc- 
tion of  45005  into  the  numerator,  c,  h,  o,  s,  and  w 
represent  respectively  the  percentages  of  carbon,  hy- 
drogen, oxygen,  sulphur,  and  water  contained  in  the 
coal.  The  water  formed  by  the  combustion  of  hydro- 
gen is  considered  to  be  in  the  vaporous  condition. 

The  results  obtained  by  these  formulas,  while  rea- 
sonably correct  for  bituminous  coal,  for  anthracite 
coal  are,  as  a  rule,  considerably  too  low. 

Goutal  has  proposed  the  formula: 

14670^  +  A  X  M 
Heating  value  =  — 

100 

c  here  represents  the  percentage  of  fixed  carbon  (coke 

-  ash);  M  the  percentage  of  volatile  matter  100  - 

(coke    +  ash  +  water)  and  A  is   a   coefficient   which 

varies  with  the  amount  of  volatile  matter  M  as  follows: 

M  =  2  to  15  A  =  23400 

15  to  30  18000 

30  to  35  17100 

35  to  40  16200 

The  results  upon  a  series  of  American  coals  varied 
less  than  2  per  cent,  from  those  obtained  by  the  bomb 
calorimeter. 

LIQUID   FUELS 

These  consist  of  petroleum  and  its  products  and 
various  tarry  residues  from  processes  of  distillation,  as 


FUELS    AND    THEIR    ANALYSIS  65 

from  petroleum,  coking  ovens,  wood  and  shale.  The 
advantages  of  liquid  fuel  are  its  increased  heating 
power,  the  decreased  labor  employed  in  its  use,  and 
its  ease  of  manipulation.  The  burners  oftentimes  re- 
quire no  change  for  a  day  at  a  time,  and  there  being  no 
fire  doors  to  open,  the  inrush  of  cold  air,  causing  strains 
in  the  boiler,  is  obviated.  Not  the  least  of  its  advan- 
tages are  its  cleanliness  and  freedom  from  smoke,  cin- 
ders, and  ash.  Owing  to  the  increase  in  heating  power 
the  boiler  can  be  smaller  and  do  the  same  work. 

The  origin  and  obtaining  of  petroleum  will  be  de- 
scribed in  Chapter  VI. 

Crude  petroleum  varies  greatly  in  color  according 
to  the  locality.  It  is  usually  yellowish,  greenish,  or 
reddish  brown,  of  benzine-like  odor,  and  specific  grav- 
ity of  0.78  to  0.80.  It  "flashes"  at  the  ordinary  tem- 
perature; hence  great  care  should  be  employed  in  its 
use  and  storage.  Its  percentage  composition  is  shown 
below : 

Carbon  Hydrogen 

84  to  85  16  to  15 

It  is  more  than  twice  as  efficient  as  the  best  anthracite 
coal,  giving  in  practice  an  evaporation  of  14  to  16 
pounds  of  water  per  pound  of  petroleum,  or  an  effi- 
ciency of  19,000  B.t.u.  as  against  8500  B.t.u.  for  an- 
thracite. In  general,  3^  to  4  barrels  of  oil,  of  50 
gallons,  are  equivalent  to  a  ton  of  good  soft  coal. 

The  various  tarry  residues  would  probably  not  differ 
materially  from  Russian  petroleum  residues,  which 
have  an  evaporating  power  of  about  13  pounds  of  water 
per  pound  of  residue. 


66 


ENGINE-ROOM    CHEMISTRY 


The  only  two  tests  that  it  is  important  to  make  upon 
liquid  fuels  are  the  flash  test  described  in  the  chapter 
upon  oil,  page  1 50,  and  heating  value,  for  which  the 
Junkers'  gas  calorimeter  may  be  used,  which  is  de- 
scribed in  "  Gas  and  Fuel  Analysis  for  Engineers." 
The  bomb  calorimeter,  or  Parr's,  may  also  be  used. 
The  flash  test,  which  should  at  least  be  as  high  as 
that  of  kerosene  oil,  about  100  deg.  F.,  is  important 
as  indicating  the  degree  of  safety  of  the  oil  when 
handling  it. 

The  table  shows  the  heating  values  and  some  other 
constants  of  some  liquid  fuels. 


Flash, 

Fire, 

Heat  Val. 

Sp. 

Sp.  Gr. 

Deg.F. 

Deg.F 

B.t.u. 

Heat 

per  Ib. 

76°  B.  Naphtha1 

76.50  B. 





18080 

o-55 

62°  B.  Naphtha1 

61.0 

— 

— 

17860 

0.50 

135°  F.  Fire  T.  Kerosene1 

48.0 

I25 

135 

17810 

0.50 

150°  F.  FireT.  Kerosene1 

48.0 

134 

15° 

18290 

0.49 

Beaumont  Crude2 

0.924 

1  80 

200 

19060 

— 

'California2 

0.966 

230 

311 

18667 

— 

California  and  Texas2 

0.966 

270 

280 

19215 

— 

Pennsylvania3 

0.886 

— 

— 

19224 

— 

Wyoming3 

0.996 

— 



19668 

— 

Residuum,  Va.3 

0.860 

— 

— 

19200 

— 

Residuum,  Russian3 

0.884 

— 



10926 

— 

1  Gill  and  Healey,  Technology  Quarterly,  xv  (1002),  74. 

2  Report  U.  S.  Naval  "  Liquid  Fuel"  Board  (1904). 

3  Poole,  "  The  Caloriac  Power  of  Fuels"  (1898). 


FUELS  AND.  THEIR  ANALYSIS  67 

GASEOUS   FUELS 

The  use  of  gaseous  fuel,  although  finding  application 
only  of  late  years,  dates  back  a  full  century.  Lam- 
padius,  in  Freiberg  in  1801,  utilized  the  waste  gases 
from  the  carbonization  of  wood,  and  Aubertot,  in  181 1, 
those  from  the  blast  furnace.  It  is,  however,  to  the 
labors  of  du  Faur,  in  Wurtemberg  in  1837,  that  the 
present  extended  use  of  gaseous  fuel  is  largely  due. 
Gaseous  fuel  is  of  three  different  types:  i.  Natural 
gas.  2.  Producer  and  blast  furnace  gas.  3.  Coal 
and  water  gas. 

Natural  gas  is  often  obtained  when  boring  for 
petroleum,  or  wells  are  especially  drilled  for 
it.  It  is  mainly  composed  of  methane  or  marsh  gas, 
and  hydrogen,  the  percentage  varying  with  the 
locality. 

Producer  gas  is  made  from  hard  or  soft  coal  in  a 
gas  producer  or  generator,  by  blowing  a  stream  of  air 
up  through  a  deep  bed  of  fuel.  The  coal  is  first  burned 
to  carbonic  acid  and  this  is  reduced  to  carbonic  oxide 
by  the  upper  layers  of  fuel.  It  is  largely  nitrogen 
with  carbonic  oxide  and  some  hydrogen. 

Gas  producers  are  of  two  classes:  (a)  those  in  which 
a  blast  of  air  is  blown  up  through  them,  usually  by  a 
jet  of  steam;  and  (b)  suction  producers,  which  are 
usually  coupled  directly  to  gas  engines,  in  which  the 
movement  of  the  engine  piston  serves  to  suck  air 
through  the  fuel. 

(a)  Producers  with  blast  (pressure  producers).  Mond, 
Miller,  Dowson,  Siemens,  Morgan,  and  Taylor  are  some 


68 


ENGINE-ROOM    CHEMISTRY 


of  the  inventors  whose  names  are  connected  with  this 
form  of  generators,  of  which  the  latter,  shown  in  Fig.  24, 
may  be  taken  as  a  type.  This  consists  of  a  boiler-iron 
shell  about  15  feet  in  hight  and  10  feet  in  diameter, 
lined  with  firebrick.  The  grate  is  a  solid  iron  plate 


FIG.  24.  —  Taylor  Gas 
Producer 


which  is  rotated,  thus  permitting  the  ashes  to  be  re- 
moved by  forcing  them  against  stationary  iron  rods. 
Peep  holes  through  the  walls  give  an  idea  of  the  hight 
to  which  the  ashes  rise.  An  automatic  feeding  device, 
a  pipe  for  the  steam-produced  blast  and  an  exit  tube 
for  the  gases  complete  the  apparatus.  This  construe- 


FUELS    AND    THEIR    ANALYSIS  69 

tion  embodies  the  conditions  necessary  for  a  successful 
gas  producer,  which  are : 1 

First,  a  continuous  and  automatic  feed,  which  in- 
sures regular  and  uniform  production  of  gas. 

Second,  a  deep  bed  of  fuel  and  a  deep  bed  of  ashes. 
A  deep  bed  of  fuel  is  essential  for  the  reduction  to 
carbonic  oxide  of  the  carbonic  acid  first  formed;  and 
a  deep  bed  of  ashes  insures  the  combustion  of  all  the 
coal. 

Third,  a  level  support  for  the  fuel  and  ashes,  which 
gives  an  even  depth  of  fuel  over  the  whole  furnace.  If 
the  grate  slants,  the  fuel  is  thicker  at  one  point  than 
another,  producing  consequently  an  uneven  quality  of 
gas. 

Fourth,  the  blast  is  carried  by  a  pipe  nearly  through 
the  deep  bed  of  ashes,  which  requires  a  lower  pressure 
of  steam  and  blast.  Last,  but  not  least,  the  hight  to 
which  the  ashes  rise  is  visible  and  they  are  easily  re- 
movable through  apertures  provided  for  the  purpose. 

A  producer  of  the  size  given  will  gasify  6t  tons  of 
anthracite  pea  coal  or  8  tons  of  bituminous  coal  in 
twenty-four  hours:  about  170,000  cu.  ft.  of  gas  of 
138  B.t.u.  per  cubic  foot  are  produced  per  ton  of 
anthracite  coal,  which  corresponds  to  a  conversion 
of  about  85  per  cent. 

(b)  Suction  producers.  In  this  type  the  movement 
of  the  gas-engine  piston  sucks  the  air  necessary  for 
gas-making  through  the  bed  of  fuel.  The  gas  passes 
through  an  economizer  containing  water,  the  steam  of 

1  Based  on  "Gas  Producers  and  Producer  Gas  Power  Plants,"  R.  D.  Wood  & 
Co.,  Philadelphia,  Pa. 


70  ENGINE-ROOM    CHEMISTRY 

which  is  conducted  beneath  the  producer  grate  and 
sucked  up  with  the  air.  On  leaving  the  economizer 
the  gas  goes  to  a  coke  scrubber,  where  it  is  sprayed  with 
water  to  remove  the  dust  and,  if  necessary,  to  a  saw- 
dust purifier  and  thence  to  the  engine.  A  gas-holder 
is  not  needed,  as  with  a  pressure  producer,  although  a 
regulator  is  often  employed.  For  starting  the  pro- 
ducer a  hand-  or  power-driven  fan  is  employed. 

It  is  claimed  for  gas  producers  that  they  require 
less  space  than  a  steam  plant  of  equal  size,  and 
whereas  the  first  cost  and  labor  charges  for  installa- 
tion are  rather  less  than  of  steam,  the  running 
expense  for  labor,  repairs,  and  maintenance  are  con- 
siderably less.  A  marked  feature  of  a  producer-gas 
plant  is  the  readiness  of  operation  and  economy  of 
fuel  during  hours  of  idleness.  Another  feature  is  the 
complete  absence  of  smoke.  It  is  further  stated  that 
with  coal  at  $2.50  to  $3.00  per  ton  producer  gas 
costs  at  the  furnaces  or  engines  about  10  cents  per 
1000  cubic  feet. 

From  anthracite  coal  at  $5  per  ton,  one  brake  horse- 
power per  hour  per  pound  of  coal;  can  be  obtained 
at  a  cost  of  0.25  cent,  with  bituminous  coal  at  $2.50 
per  ton,  one  and  a  quarter  pounds  of  coal  are  used, 
at  a  cost  of  0.1565  cent  per  brake  horse-power  per 
hour. 

Blast-furnace  gas  is  the  gas  issuing  from  the  top  of 
an  iron  blast  furnace,  and  is  practically  of  the  same 
composition  as  producer  gas.  It  has  been  used  to  run 
gas  engines  at  the  Cockerill  Company's  works  at  Se- 
raing,  Belgium,  and  at  the  Lackawanna  Steel  Com- 


FUELS    AND    THEIR    ANALYSIS  71 

pany's  plant  at  Buffalo  for  a  number  of  years  with 
good  success,  in  units  of  200  to  2000  horse-power. 

The  calculation  has  been  made  that  by  using  the  gas 
from  three  blast  furnaces  a  saving  of  $150,000  per  year 
in  power  could  be  made  by  the  use  of  gas  engines,  at  an 
outlay  of  $500,000.  The  prediction  is  made  that  by 
the  utilization  of  these  gases  for  power  purposes  metal- 
lurgical plants  may  become  important  centers  of  power. 

The  analysis  of  these  various  gases  is  shown  in  the 
table  below. 

Coal  Gas. — One  method  of  the  manufacture  of  coal 
gas  has  already  been  described  under  the  heading  coke, 
using  there  the  Otto-Hoffman  or  Semet-Solvay  by- 
products ovens.  In  addition  to  these,  coal  is  distilled 
in  D-shaped  clay  retorts,  primarily  for  the  purpose  of 
making  gas,  —  coke,  tar,  etc.,  being  by-products.  Coal 
gas  is  largely  methane  and  hydrogen  with  small  per- 
centages of  "illuminants"  and  carbonic  oxide.  Its  il- 
luminating power  is  from  sixteen  to  nineteen  candles. 

Water  Gas. — As  its  name  denotes,  a  gas  made  from 
water  by  decomposing  it  with  coal  at  a  high  tempera- 
ture: 

Coal  +  water  =  water  gas 

Carbon  +  hydrogen  oxide  =  carbonic  oxide  +  hydrogen 

If  we  pass  steam,  instead  of  air, — as  in  a  producer,  — 
over  hot  coal,  it  is  decomposed,  giving  carbonic  oxide 
and  hydrogen.  From  the  flame  it  produces  on  burn- 
ing, it  is  called  "  blue  "  water  gas.  To  make  it  luminous 
and  enable  it  to  be  used  as  an  illuminant,  it  is  enriched 
by  blowing  petroleum  vapor  into  it,  "gas  oil,"  and 


ENGINE-ROOM    CHEMISTRY 


passing  the  mixture  through  hot  checker  work,  decom- 
posing the  vapor,  or  "fixing  it,"  into  permanent  gases 
of  high  illuminating  power.  The  illuminating  power 
of  enriched  water  gas  is  from  twenty-five  to  twenty- 
eight  candles. 

COMPOSITION  OF  SOME  GASEOUS  FUELS 


Meth- 
thane 

Hydro- 
gen 

Illumi- 
nants 

Carb. 
acid 

Carb. 
oxide 

Oxy- 
gen 

Nitro- 
gen 

B.  t.u. 
pr.  cu.ft. 

Ohio 

93-3 

1.6 

°-3 

0.2 

0.4 

0.4 

3-6 

I02O1'2 

Pennsyl- 

vania 

89.6 

4.9 

5-° 

o-3 

0-3 

— 

— 

I0732 

Producer 

pressure 

— 

I2.O 

— 

2-5 

27.0 

0-3 

57-o 

145 

Producer 

suction 

°-5 

l8.5 

— 

8.0 

26.0 

— 

47  -o 

145 

Blast 

furnace 

— 

1.4 

— 

0.6 

34-3 

— 

63-7' 

122 

Coal 

34-8 

50.6 

5-2 

1.2 

6.2 

— 

2.1 

5992 

Enriched 

water 

19.1 

31-3 

15.0 

3-° 

27.4 

0.4 

3-8 

7362 

Blue 

water 

0.8 

52-4 

— 

4.6 

41-5 

— 

0-5 

3322 

Wood 

2.9 

°-5 

0.6 

11  -5 

28.4 

— 

56-1 

i452 

Peat 

2.7 

0.9 

04 

12.  1 

27.2 

56.7 

i382 

1  0.2  per  cent,  hydrogen  sulphide. 

2  From  Poole,  "  The  Calorific  Power  of  Fuels.' 


IV 


THE    REGULATION    OF  .  COMBUSTION —  GAS 
ANALYSIS 

THE  fuels  themselves  were  treated  of  in  the  last 
chapter,  and  were  it  not  for  the  fact  that  the  appli- 
ances for  their  application  would  take  us  too  far  from 
our  subject,  these  would  be  next  discussed.1 

Before  leaving  the  topic  of  the  methods  of  burning 
coal,  just  a  word  should  be  said  regarding  the  use  of 
various  chemicals  mixed  with  or  dissolved  in  water 
and  sprinkled  upon  the  coal,  it  being  claimed  that  they 
aid  combustion.  Such  are  "  Kern-Kern,"  "  Koal  Spar," 
"  Koala  Sava,"  2  "  Fuel  Savers,"  etc.,  which  consist 
mainly  of  salt  with  a  small  percentage  of  something 
furnishing  oxygen  at  a  high  heat,  as  saltpeter.  One 
of  these  compounds  2  was  of  the  following  composition : 
2000  Ib.  salt,  100  Ib.  copperas,  25  Ib.  charcoal,  15  Ib. 
niter,  and  15  Ib.  cooking  soda.  Three  pounds  of  this 

1  These  will  be  found  described  at  length  in :  Groves  and  Thorp,  "  Chem- 
ical Technology,"  vol.  i;  Mills  and  Rowan,  "Fuels"  (1889);  Barr,  "Boilers  and 
Furnaces";  Christie,  in  Engineering  Magazine,   xxiii   (1902),   528,717;   E.  A.  B. 
Hodgetts,  "Liquid  Fuels";  Report  of  the  U.  S.  Naval  "Liquid  Fuel"  Board,  Wash- 
ington, 1904;    Williston,  in  Engineering  Magazine,  xxiv  (1903),  237;   Professional 
Paper  No.  48:  Report  on  the  Operations  of  the  Coal-Testing  Plant  of  the  U.  S. 
Geological  Survey  at  St.  Louis,  1904,  parts  I,  II,  and  III,  Washington,  1906;  also 
"Gas  Producers,"  and  "Gas  Fuel,"  circulars  of  R.  D.  Wood  &  Co.,  Philadelphia, 
Pa. 

2  Journal  Society  Chemical  Industry,  xxi  (1902),  330. 

73 


74  ENGINE-ROOM    CHEMISTRY 

was  to  be  "dissolved"  in  water  and  sprinkled  on  a  ton 
of  coal.  Used  in  this  way,  about  one-third  of  an  ounce 
of  niter  would  be  furnished  per  ton  of  coal,  which  would 
yield  about  three  pints  of  oxygen  gas.  As  210  cu.  ft. 
of  air  are  required  per  pound  of  coal,  or  420,000  cu.  ft. 
per  ton,  the  effect  of  these  three  pints  of  oxygen  in  this 
quantity  of  air  can  be  easily  imagined. 

Some  of  these  compounds  have  even  been  patented, 
and  of  this  the  eminent  German  engineer,  Professor 
Ferdinand  Fischer,  says:  "Such  nonsense  should  not 
be  patentable."  l  In  a  test  which  came  to  the  writer's 
notice  no  gain  could  be  seen  by  the  use  of  these  com- 
pounds. 

Combustion  is  usually  regulated  by  a  more  or  less 
arbitrary  opening  and  closing  of  the  dampers  or  by 
damper  regulators.  It  is  more  and  more  coming  to  be 
governed  by  an  examination  of  the  "smoke  gases/'  as 
they  are  called,  or  the  chimney  gases.  This  may  be 
done  either  by  occasional  chemical  analysis  or  by  cer- 
tain automatic  apparatus  which  are  in  operation  con- 
tinuously. 

A.  EXAMINATION  OF  CHIMNEY  GASES  BY  CHEMICAL 
ANALYSIS 

To  this  end  a  sample  of  the  gases  must  be  drawn 
from  the  chimney  into  the  gas  apparatus  where  the 
various  components  are  determined. 

Sampling  Apparatus.  A  glass  tube  f  in.  in  diameter 
and  about  three  feet  long,  drawn  down  to  |  in.  at  one 

1  Solcher  Unsinn  sollte  nicht  patentirbar  sein. 


REGULATION    OF    COMBUSTION  75 

end,  is  inserted  into  the  uptake  or  smoke-pipe  leading 
to  the  chimney,  on  the  grate  side  of  the  damper.  For 
this  purpose  a  }-in.  hole  is  drilled  into  this  duct  or 
pipe,  and  the  space  around  the  tube  stopped  with  putty, 
plaster  of  Paris,  or  wet  cotton  waste.  The  tube  should 
be  inserted  for  about  half  its  length,  and  the  place 
chosen  for  its  insertion  should  be  as  near  the  point 
where  the  gases  leave  the  boiler  as  possible,  so  that  a 
representative  sample  may  be  secured.  The  object 
in  this  is  to  prevent  the  contamination  of  the  combus- 
tion gases  by  leakage  of  air  through  cracks  in  the 
clean-out  doors  and  setting,  and  also  where  the  damper 
is  fitted:  all  these  places  should  be  plastered  up,  as  the 
leakage  through  them  or  even  through  a  brick  wall  is 
not  inconsiderable.  In  some  cases  it  will  be  found  that 
the  draft  is  materially  increased  by  the  sizing  and 
whitewashing  of  the  boiler  setting.  In  making  a  test 
of  chimney  gases  all  openings  other  than  the  legitimate 
ones  for  draft  should  be  carefully  closed.  It  is  well  also 
to  place  in  the  tube  two  rolls  of  fine  wire  gauze  three 
inches  long,  to  strain  out  the  soot. 

Some  means  of  sucking  out  the  sample  of  gas  must 
now  be  provided.  Where  samples  are  taken  infre- 
quently, an  ordinary  double-ended  rubber  syringe 
bulb,  provided  with  suitable  hard-rubber  valves,  may 
be  used.  Better  than  this,  and  possessing  the  advan- 
tages of  permanency,  and  ease  and  rapidity  of  opera- 
tion, is  some  form  of  water-jet  pump  as  the  Richards 
(Fig.  25)  or  Chapman's;  these  are  constructed  and 
operate  like  the  familiar  boiler  injector;  and,  if  water 
be  inconvenient  of  access,  steam  may  be  used  instead. 


76 


ENGINE-ROOM    CHEMISTRY 


A  piece  of  |-in.  rubber  tubing  is  connected  to  the  air 
intake  and  the  tubing  attached  to  the  sampling  tube 
in  the  flue.  Where  long  runs  of  tubing  are  needed  it 
will  be  found  cheaper  to  employ  |-in.  lead  pipe,  using 
short  pieces  of  rubber  tubing  to  give  flexibility  to  the 
connections.  As  few  rubber  connections  as  possible 
should  be  used,  as  they  deteriorate  and  give  rise  to 


Glass 
Tube 


Putty 


T   Tube 


To  Orsat 
Apparatus 


Jet  Pump 


Foam 


FIG.  25. —  Arrangement  of  Apparatus  to  take  a  Sample  of  Gas 

leaks.  "Cup  joints"  made  with  soldering-iron  are  to 
be  preferred.  A  lead  T  with  a  rubber  connector  and 
pinch-cock  connecting  with  the  gas  analytical  appa- 
ratus is  inserted  in  the  rubber  tubing  and  we  are  ready 
to  take  a  sample  of  chimney  gas.  The  arrangement 
of  the  apparatus  is  shown  in  Fig.  25. 
To  take  a  sample  of  gas  the  pump  is  started  and  a 


REGULATION    OF    COMBUSTION  77 

stream  of  gas  sucked  out  from  the  chimney  down  into 
the  pump.  The  burette  in  the  gas  apparatus  having 
been  filled  with  water,  the  pinch-cock  a  is  opened  and 
enough  gas  sucked  into  the  burette  to  displace  any  air 
in  the  stem  of  the  T-tube  and  its  connections.  This  is 
expelled  by  pinching  the  rubber  connector,  thereby 
making  a  channel  in  it  through  which  finally  the  con- 
fining water  drips.  The  gas  is  sucked  in  again  until 
rather  more  than  100  cc.  are  brought  into  the  burette. 

GAS  ANALYTICAL  APPARATUS 

In  the  writer's  opinion  1  the  apparatus  which  is  best 
adapted  for  this  purpose  is  that  of  Orsat :  it  is  readily 
portable,  not  liable  to  be  broken,  easy  to  manipulate, 
sufficiently  accurate,  and,  in  the  modification  about  to 
be  described,  always  ready  for  use,  there  being  no 
stop-cocks  to  stick  fast. 

Orsat  Apparatus.  —  Description.  The  apparatus 
(Fig.  26)  is  enclosed  in  a  case  to  permit  of  trans- 
portation from  place  to  place;  furthermore,  the  meas- 
uring-tube is  jacketed  with  water  to  prevent  changes 
of  temperature  affecting  the  gas-volume.  The  ap- 
paratus consists  essentially  of  the  leveling-bottle  A, 
the  burette  B,  the  pipettes  P1 ',  P",  P'" ,  and  the  con- 
necting tube  T.  To  set  up  the  apparatus,  the  bottle  A 
and  burette  B  are  connected  by  the  long  piece  of 
J-in.  rubber  tubing;  similarly  B  and  the  pipettes  Pf, 
P",  P'"  are  connected  with  the  connecting  tube  T  by 
rubber  connectors  carrying  pinch-cocks;  lastly,  the 

1  J.  M.  Morehead,  143  Lake  Street,  Chicago,  has  devised  an  apparatus,  a  de- 
scription of  which  is  just  at  hand,  which  would  seem  to  have  many  good  points. 


78  ENGINE-ROOM    CHEMISTRY 

rubber  connector  and  pinch-cock  d  are  placed  in  posi- 
tion upon  the  end  of  T.  The  water-jacket  is  filled, 
preferably  with  distilled  water,  and  about  150  cc.  of 
water  put  into  the  bottle.  Pipette  P'  is  filled  about 
half-full  of  potassium  hydrate  by  removing  the  stop- 
pers carrying  the  bent  tube  and  rubber  bag;  all  the 


FIG.  26.  —  Orsat's  Gas  Apparatus 

pinch-cocks  but  d  being  closed,  the  bottle  A  is  raised 
and  the  burette  filled  with  water  nearly  to  the  con- 
nector; d  is  closed,  and  e,  the  pinch-cock  upon  Pf, 
opened,  the  bottle  lowered,  thus  sucking  the  reagent 
up  into  the  front  limb  of  P'  and  nearly  to  the  capil- 
lary; sufficient  reagent  is  poured  into  the  rear  limb 


REGULATION    OF    COMBUSTION  79 

of  P*  to  leave  about  a  half-inch  of  liquid  standing  in 
it  when  the  reagent  is  in  its  capillary  stem. 

Manipulation.  The  reagents  in  the  pipettes  should 
be  adjusted  in  the  capillary  tubes  to  a  point  on  the 
stem  about  midway  between  the  top  of  the  pipette 
and  the  rubber  connector.  This  is  effected  by  opening 
wide  the  pinch-cock  upon  the  connector,  the  bottle 
being  on  the  table,  and  very  gradually  lowering  the 
bottle  until  the  reagent  is  brought  to  the  point 
above  indicated.  Six  inches  of  the  tubing  used  cor- 
respond to  but  o.i  cc.,  so  that  an  error  of  a  half-inch 
in  adjustment  of  the  reagent  is  without  influence 
upon  the  accuracy  of  the  result.  The  reagents  hav- 
ing been  thus  adjusted,  the  burette  and  connecting 
tube  are  completely  filled  with  water  by  opening  d 
and  raising  the  leveling-bottle.  The  apparatus  is 
now  ready  to  receive  a  sample  of  gas  (or,  for  practice, 
air).  The  burette,  after  being  filled,  is  allowed  to 
drain  one  minute  by  the  sand-glass,  c  is  snapped 
upon  its  rubber  tube,  and  the  bottle  A  raised  to 
the  top  of  the  apparatus.  By  gradually  opening  c, 
the  water  is  allowed  to  run  into  the  burette  until  the 
lower  meniscus  stands  upon  the  100  or  the  o  mark 
(according  to  the  graduation  of  the  apparatus).  The 
gas  taken  is  thus  compressed  into  the  space  occupied 
by  100  cc.,  and,  by  opening  d,  the  excess  escapes. 
Open  c,  bring  the  level  of  the  water  in  the  bottle  to  the 
same  level  as  the  water  in  the  burette,  and  take  the 
reading,  which  should  be  100  cc.  Special  attention  is 
called  to  this  method  of  reading:  if  the  bottle  be  raised, 
the  gas  is  compressed;  if  lowered,  it  is  expanded. 


8o  ENGINE-ROOM    CHEMISTRY 

Determination  of  Carbon  Dioxide.  The  gas  to  be 
analyzed  is  invariably  passed  first  into  the  pipette 
P' ,  containing  the  potassium  hydrate  for  the  absorp- 
tion of  carbon  dioxide  ("carbonic  acid"),  by  Opening 
e  and  raising  A.  The  gas  displaces  the  reagent  in  the 
front  part  of  the  pipette,  laying  bare  the  tubes  con- 
tained in  it,  which,  being  covered  with  the  reagent, 
present  to  the  gas  a  large  absorptive  surface;  the  re- 
agent moves  into  the  rear  arm  of  the  pipette,  displa- 
cing the  air  over  it  into  the  flexible  rubber  bag,  which 
prevents  its  diffusion  into  the  air.  The  gas  is  forced 
in  and  out  of  the  pipette  by  raising  and  lowering  A,  the 
reagent  is  finally  brought  approximately  to  its  initial 
point  on  the  stem  of  the  pipette,  the  burette  allowed  to 
drain  one  minute,  and  the  reading  taken.  The  differ- 
ence between  this  and  the  initial  reading  represents 
the  cubic  centimeters  of  carbon  dioxide  present  in  the 
gas.  To  be  certain  that  all  the  carbon  dioxide  is  re- 
moved, the  gas  should  be  passed  the  second  time  into 
Pf  and  the  reading  taken  as  before.  These  two  readings 
should  agree  within  o.  i  per  cent. 

Determination  of  Oxygen.  The  residue  from  the 
absorption  of  carbon  dioxide  is  passed  into  the  sec- 
ond pipette,  P",  containing  an  alkaline  solution  of 
potassium  pyrogallate,  until  no  further  absorption 
will  take  place.  The  difference  between  the  reading 
obtained  and  that  after  the  absorption  of  carbon  diox- 
ide represents  the  number  of  cubic  centimeters  of  oxy- 
gen present. 

Determination  of  Carbonic  Oxide.  The  residue 
from  the  absorption  of  oxygen  is  passed  into  the 


REGULATION    OF    COMBUSTION  81 

third  pipette,  P'" ',  containing  cuprous  chloride,  until 
no  further  absorption  takes  place;  that  is,  in  this  case, 
until  readings  agreeing  exactly  (not  merely  to  o.i)  are 
obtained.  The  difference  between  the  reading  thus 
obtained  and  that  after  the  absorption  of  oxygen  rep- 
resents the  number  of  cubic  centimeters  of  carbonic 
oxide  present. 

Determination  of  Hydrocarbons.  The  residue  left 
after  all  absorptions  have  been  made  may  consist 
in  addition  to  nitrogen,  the  principal  constituent,  of 
hydrocarbons  and  hydrogen.  Their  determination  is 
difficult  for  the  inexperienced.  If  desired,  a  sample 
of  the  flue-gas  should  be  taken,  leaving  as  little  water 
in  the  apparatus  as  possible,  and  sent  to  a  competent 
chemist  for  analysis. 

Accuracy;  Time  Required.  The  apparatus  gives 
results  accurate  to  0.2  of  i  per  cent. 

About  twenty  minutes  are  required  for  an  analysis; 
but  using  two  apparatus,  two  analyses  may  be  made 
in  twenty-five  minutes. 

Notes.  The  above-described  method  of  adjusting 
the  reagents  is  the  only  one  that  has  been  found  satis- 
factory: if  the  bottle  be  placed  at  a  lower  level  and  an 
attempt  made  to  shut  the  pinch-cock  c  upon  the  con- 
nector at  the  proper  time,  it  will  almost  invariably 
result  in  failure. 

The  process  of  obtaining  100  cc.  of  gas  is  exactly 
analogous  to  filling  a  measure  heaping  full  of  grain  and 
striking  off  the  excess  with  a  straight-edge:  it  saves 
arithmetical  work,  as  cubic  centimeters  read  off  repre- 
sent percentage  directly. 


82  ENGINE-ROOM    CHEMISTRY 

It  often  happens  when  e  is  opened,  c  being  closed, 
that  the  reagent  in  Pf  drops.  This  is  due  not  to  a  leak 
as  is  usually  supposed,  but  to  the  weight  of  the  column 
of  the  reagent  expanding  the  gas. 

The  object  of  the  rubber  bags  is  to  prevent  the  access 
of  air  to  the  reagents,  those  in  P"  and  P"r  absorbing 
oxygen  with  great  avidity;  hence,  if  freely  exposed  to 
the  air,  they  would  soon  become  useless. 

Carbon  dioxide  is  always  the  first  gas  to  be  removed 
from  a  gaseous  mixture.  In  the  case  of  air  the  per- 
centage present  is  so  small,  0.08  to  o.i,  as  scarcely  to 
be  seen  with  this  apparatus.  It  is  important  to  use 
the  reagents  in  the  order  given :  if  by  mistake  the  gas 
be  passed  into  the  second  pipette,  it  will  absorb  not 
only  oxygen,  for  which  it  is  intended,  but  also  carbon 
dioxide;  similarly,  if  the  gas  be  passed  into  the  third 
pipette,  it  will  absorb  not  only  carbonic  oxide,  but  oxy- 
gen as  well. 

The  use  of  pinch-cpcks  and  rubber  tubes,  original 
with  the  author,  although  recommended  by  Naef,  is 
considered  by  Fischer  to  be  inaccurate.  The  experi- 
ence of  the  author  during  fifteen  years,  however,  does 
not  support  this  assertion,  as  they  have  been  found  to 
be  fully  as  accurate  as  glass  stop-cocks,  and  very  much 
less  troublesome  and  expensive. 

In  case  any  potassium  hydrate  or  pyrogallate  be 
sucked  over  into  the  tube  T,  or  water  in  A,  the  analy- 
sis is  not  spoiled,  but  may  be  proceeded  with  by  con- 
necting on  water  at  d,  opening  this  cock,  and  allowing 
the  water  to  wash  out  the  tubes  thoroughly.  The  ad- 
dition of  a  little  hydrochloric  acid  to  the  water  in  the 


REGULATION    OF    COMBUSTION  83 

bottle  A  will  neutralize  the  hydrate  or  pyrogallate, 
and  the  washing  may  be  postponed  until  convenient. 

After  each  analysis  the  number  of  cubic  centimeters 
of  oxygen  and  carbonic  oxide  should  be  set  down  upon 
the  ground-glass  slip  S  provided  for  the  purpose.  By 
adding  these  numbers  and  subtracting  their  sum  from 
the  absorption  capacity  (see  V Reagents")  of  each  re- 
agent, the  condition  of  the  apparatus  can  be  ascer- 
tained at  any  time,  and  the  reagent  can  be  removed  in 
season  to  prevent  incorrect  analyses. 

Reagents.  —  The  reagents  used  with  the  foregoing 
apparatus  are  prepared  as  follows: 

Hydrochloric  Acid  (Sp.  gr.  i.io).  Dilute  "muri- 
atic acid"  with  an  equal  volume  of  water.  In  addi- 
tion to  its  use  for  preparing  cuprous  chloride,  it  is 
employed  in  neutralizing  the  caustic  solutions  which 
are  unavoidably  more  or  less  spilled  during  their  use. 

Acid  Cuprous  Chloride.  The  directions  given  in 
the  various  text-books  being  troublesome  to  execute, 
the  following  method,  which  is  simpler,  has  been  found 
to  give  equally  good  results.  Cover  the  bottom  of  a 
quart  bottle  with  a  layer  of  copper  oxide  or  "scale" 
f  in.  deep;  place  in  the  bottle  a  number  of  pieces  of 
rather  stout  copper  wire  reaching  from  top  to  bottom, 
sufficient  to  make  a  bundle  one  inch  in  diameter,  and 
fill  the  bottle  with  common  hydrochloric  acid  of  i.io 
sp.  gr.  Shake  the  bottle  occasionally,  and  when  the 
solution  is  colorless,  or  nearly  so,  pour  it  into  a  smaller 
bottle  for  filling  the  gas  pipette  containing  copper  wire, 
ready  for  use.  The  space  left  in  the  stock  bottle  should 
be  immediately  filled  with  hydrochloric  acid  (i.io  sp. 


84  ENGINE-ROOM    CHEMISTRY 

gr.).  By  thus  adding  acid  or  copper  wire  and  copper 
oxide  when  either  is  exhausted,  a  constant  supply  of 
this  reagent  may  be  kept  on  hand. 

The  absorption  capacity  of  the  reagent,  according 
to  the  author's  experience  with  Orsat's  apparatus,  is 
its  own  volume  of  carbon  monoxide. 

Care  should  be  taken  that  the  copper  wire  does  not 
become  entirely  dissolved,  and  that  it  extends  from 
the  top  to  the  bottom  of  the  bottle;  furthermore  the 
stopper  should  be  kept  thoroughly  greased  the  more 
effectually  to  exclude  the  air,  which  turns  the  solution 
brown  and  weakens  it. 

Potassium  Hydrate,  (a)  For  carbon  dioxide  de- 
termination 500  grams  of  the  commercial  hydrate  are 
dissolved  in  i  liter  (quart)  of  water.  Absorption  capac- 
ity: i  cc.  absorbs  40  cc.  CO2. 

(b)  For  the  preparation  of  potassium  pyrogallate 
for  special  work,  120  grams  of  the  commercial  hydrate 
are  dissolved  in  100  cc.  of  water. 

Potassium  Pyrogallate.  The  most  convenient 
method  of  preparation  is  to  weigh  out  5  grams  of  the 
solid  acid  upon  a  paper,  pour  it  into  a  funnel  inserted 
in  the  gas  pipette  and  pour  upon  it  100  cc.  of  potassium 
hydrate  (a)  or  (b).  The  acid  dissolves  at  once,  and  the 
solution  is  ready  for  use.  If  the  percentage  of  oxygen 
in  the  mixture  does  not  exceed  28,  solution  (a)  may  be 
used;  if  this  amount  be  exceeded,  (b)  must  be  em- 
ployed. Otherwise  carbonic  oxide  may  be  given  off 
even  to  the  extent  of  6  per  cent.  Absorption  capac- 
ity: i  cc.  absorbs  2  cc.  oxygen. 

Attention  is  called  to  the  fact  that  the  use  of  potas- 


REGULATION    OF    COMBUSTION  85 

sium  hydrate   purified   by  alcohol  has  given   rise   to 
erroneous  results. 

CALCULATIONS 

The  object  in  analyzing  the  chimney  gases  is  to  fur- 
nish additional  data  for  the  engineer  besides  those 
usually  given  by  the  evaporative  test  of  the  boiler. 
In  fact,  before  incurring  the  trouble  and  expense  of  this 
latter  test,  the  boiler  plant  should  be  tuned  up  by,  so 
to  speak,  or  submitted  to,  a  preliminary  test  or  series 
of  tests  with  a  gas  apparatus  and  a  flue  thermometer; 
the  proper  adjustment  of  dampers  should  be  made, 
and  leaks  stopped  in  the  setting. 

An  example  will  make  this  clear.  The  plant  to  be 
tested  was  one  employing  forced  draft ;  and,  as  the  g^s 
analysis  showed  a  large  excess  of  air,  the  blower  en- 
gine was  slowed  down  and  the  results  shown  below  in 
column  i  were  obtained.  A  large  excess  of  air  still 
being  shown,  the  engine  was  slowed  down  more,  giving 
the  results  shown  in  column  2;  and  even  more  than 
this,  as  shown  in  column  3. 

I1  2  3 

Heat  going  into  water 59-6  67 . 8  70 .  o 

Heat  going  into  gases 33 . 2  23 . 6  17.8 

Heat  lost  (unaccounted  for) 7.2  8.6  12.2 

Evaporation  Ib.  water  from  and  at  212  deg.     9.8  11.2  n.o 

Excess  of  air  per  cent 225.0  130.0  55 .o 

1  Other  data  of  interest  in  connection  with  this  test  are  the  following: 
Duration  of  test  14  hours;  4  horizontal  return-tubular  boilers. 
Area  of  grate  48  x  78  inches  =  104  sq.  ft.     (4  boilers; 
Area  of  water-heating  surface  =  6328  sq.  ft. 

Ratio 60.8 

Air  per  pound  coal 34 . 85 


86  ENGINE-ROOM    CHEMISTRY 

This  evaporative  test  shows  simply  the  percentage 
of  heat  absorbed  by  the  water,  and  gives  no  idea  of 
what  becomes  of  the  remainder.  The  composition  and 
temperature  of  the  gases  tell  us  what  part  of  the  heat 
is  passing  up  chimney;  the  analysis  of  the  ash,  what 
is  the  loss  due  to  unconsumed  coal:  the  chemical  ex- 
amination gives,  then,  these  further  data:  (i)  loss  in 
chimney  gases;  (2)  loss  due  to  formation  of  carbonic 
oxide;  and  (3)  loss  due  to  carbon  in  ash;  leaving  as 
unaccounted  for  only  the  loss  due  to  radiation  and 
conduction. 

The  calculations  involve  the  determination  of  the 
number  of  pounds  of  air  per  pound  of  coal,  and  the 
volume  of  gas  passing  up  chimney  with  its  tempera- 
ture; we  must  know  furthermore  the  heating  value,  or 
calorific  power,  of  the  coal. 

(i  a)  Pounds  of  Air  Per  Pounds  of  Coal. — The 
analysis  of  a  chimney  gas  gave:  carbonic  acid  11.5, 
oxygen  7.4,  carbonic  oxide  0.9,  nitrogen  80.2  per  cent. 
The  number  of  cubic  feet  of  each  of  these  gases  in  100 
cubic  feet  of  chimney  gas  would  then  be  represented 
by  these  figures,  since  the  gas  analysis  is  given  in  per- 
centage, or  parts  by  volume.  The  weight  of  each  of 
these  gases  is  found  by  multiplying  the  number  of  cubic 
feet  by  the  weight  of  a  cubic  foot.  For  example,  the 

Loss  of  heat  in  chimney  gases   33  per  cent. 

Coal  burned  per  sq.  ft.  per  hour   9 . 18  Ib. 

Water  evaporated  from  and  at  212  deg.  per  sq.  ft 1.45 

Quality  of  steam    0.980 

Coal  used,  Pocahontas  of  the  following  analysis: 

C  H  S  N  and  O        Water          Ash        Her.ting  Value 

SI.Q  4.5  TO  2.9  0.03  9.3  14.530   B.t.u. 


REGULATION    OF    COMBUSTION  8? 

weight  of  a  cubic  foot  of  carbonic  acid  is  0.1234  lb.; 
11.5  cu.  ft.  therefore  weigh  1.419  lb.  The  weights 
and  volumes  of  each  of  the  gases  are  shown  below: 

Cu.  ft.  in  100  cu.  Weight  of  one  Weight  of  gas  in 

ft.  chimney  gas  cu.  ft.  gas  in  lb.  100  cu.  ft.  in  lb. 

CO2 ii. 5                       0-1234  1-419 

CO 0.9                      .0.0781  0.070 

O 7.4                       0.0893  0.661 

Carbonic  acid  is  ||- oxygen;  that  is, 


CO2     12  +  (2  X  16)         44 


In    1.419  lb.   carbonic  acid    there  are,    then,   y8^  X 
1.419  or  1.033  lb-  oxygen  and  0.386  lb.  carbon. 
Similarly,   carbonic    oxide    is    ||  oxygen;  that  is, 


OandC 


CO     12  +  16         28          7  7 

In  0.0703  lb.  carbonic  oxide  there  are  consequently 
0.0402  lb.  oxygen  and  0.0301  lb.  carbon. 
In  100  cubic  feet  of  chimney  gas  there  are: 

In  the  CO2 i  .033  lb.  O  and  0.386  lb.  C 

In  the  CO 0.040  lb.  O  and  0.030  lb.  C 

In  the  O.  .  .  .0.661  lb.  O 


Total 1.734  lb.  O  and  0.416  lb.  C 

That  is,  for  every  0.416  lb.  carbon  there  are  1.734  lb. 
oxygen,  or  4.168  pounds  of  oxygen  per  pound  of  car- 
bon. Air  is  23.1  parts  by  weight  oxygen;  that  is,  in 
100  pounds  of  air  there  are  23.1  pounds  of  oxygen: 
4.168  pounds  of  oxygen  represent  18.04  pounds  of  air. 
There  are  therefore  in  the  chimney  gas  under  consider- 


88  ENGINE-ROOM    CHEMISTRY 

ation  18.04  pounds  of  air  per  pound  of  carbon.1  The 
coal  used  was,  however,  but  83  per  cent,  carbon;  con- 
sequently, this  figure  must  be  diminished  accordingly, 
giving  14.97  pounds  of  air  per  pound  of  coal  reckoned 
from  the  carbon.  The  oxygen  in  the  coal  combines 
with  one-eighth  of  its  weight  of  hydrogen,  and  the 
remaining  hydrogen  requires  36  pounds  of  air  per 
pound  for  combustion;  so  that 

/                     o.oo4\ 
36  I  0.0256 -  ]  =  0.88  pounds 

\  8      / 

of  air  to  combine  with  the  hydrogen. 

14.97  +  0.88  =  15.85  pounds  of  air  per  pound  of  coal. 

The  previous  calculation  is  accurate  but  tedious. 
For  rapid  technical  work  the  following  may  be  used: 
The  ratio  of  air  actually  used  to  that  theoretically 
necessary  may  be  expressed  by  the  formula 


21  -  79  O 


in  which  0  and  N  represent  the  percentages  of  oxygen 
and  nitrogen  respectively  in  the  flue  gas  as  found  by 
analysis.  Applying  it  in  this  case  we  have 


21  -  79  X  7-4       i3-7       1-533  ratl° 
80.2 

Multiplying  this  by  11.54,  the  theoretical  number  of 
pounds  of  air  per  pound  of  carbon,  we  obtain  17.69  as 
against  18.04  above.  ^ 

1  Theory  requires  11.54  lb. 


REGULATION    OF    COMBUSTION  89 

(i  b)  Percentage  of  Heat  Lost  in  Chimney  Gases. 
—  We  need  to  know  here  the  composition  and  tem- 
perature of  the  gases,  their  specific  heat,  the  chem- 
ical analysis  and  the  heating  value  of  the  coal.  The 
analysis  of  the  gases  has  just  been  given;  and  we  cal- 
culate from  this  what  volume  of  gases  of  this  com- 
position would  be  formed  from  the  combustion  of  one 
pound  of  coal.  Knowing  their  rise  of  temperature  and 
specific  heat,  we  can  calculate  the  quantity  of  heat  they 
carry  off;  and,  dividing  this  by  the  heating  value  of 
the  coal,  we  obtain  the  percentage  of  heat  passing  up 
chimney. 

The  composition  of  the  gases  is  the  same  as  given 
under  la,  "Pounds  of  air  per  pound  of  coal."  The 
chemical  analysis  of  the  coal  is:  moisture  1.5  per  cent., 
sulphur  1.2,  carbon  83.0,  hydrogen  2.5,  ash  1 1.4,  oxygen 
and  nitrogen  (by  difference),  0.4.  In  one  pound  of  coal 
there  are  0.83  Ib.  carbon;  of  this  suppose  but  0.80  Ib. 
to  be  burned,  the  remaining  0.03  Ib.  going  into  the  ash. 
As  both  carbonic  acid  and  carbonic  oxide  were  formed, 
we  must  calculate  what  part  of  the  0.80  Ib.  carbon  pro- 
duced each.  From  the  preceding  calculation  we  found 
that  the  amount  of  carbon  in  these  two  gases  was  0.416 
Ib.,  made  up  of  0.386  Ib.  coming  from  the  carbonic  acid, 
and  0.030  Ib.  from  the  carbonic  oxide:  that  is,  |||  pro- 
duced carbonic  acid,  and  -g^  produced  carbonic  oxide. 
Of  the  0.80  Ib.  carbon,  |||,  or  0.742  Ib.,  produced  car- 
bonic acid,  and  0.058  Ib.  produced  carbonic  oxide.  We 
must  next  determine  how  much  carbonic  acid  is  pro- 
duced from  0.742  Ib.  carbon.  From  the  calculation 
I  a,  of  the  pounds  of  air  per  pound  of  coal,  we  see  that 


90  ENGINE-ROOM    CHEMISTRY 

in  11.5  cubic  feet  of  carbonic  acid  there  are  0.386  Ib. 
carbon ;  or  we  may  say  that  0.386  Ib.  carbon  produces 
11.5  cu.  ft.  carbonic  acid,  and  consequently  0.742  Ib. 
would  produce  22.  i  cu.  ft. 

386  :  742::  11.5  :  x.    #  =  22.  i 

Similarly  we  see  that  0.03  Ib.  carbon  produced  0.9 
cu.  ft.  carbonic  oxide;  0.058  Ib.  carbon  therefore  pro- 
duces i  .74  cu.  ft.  carbonic  oxide. 

To  obtain  the  volume  of  oxygen,  we  can  make  the 
proportion 

per  cent,  carbonic  acid  :  per  cent,  oxygen  ::  cubic  feet  of  carbonic  acid 
:  cubic  feet  of  oxygen 

or 

11.5  :  7.4  ::  22.1:  y.    y  =  14.2  cubic  feet. 

In  the  same  way  we  can  determine  the  volume  of  the 
nitrogen. 

1 1 . 5  :  80 . 2  : :  22 .  i :  z.     2=154.1  cubic  feet  nitrogen. 

One  pound  of  coal  burned  to  form  a  chimney  gas  of 
the  volumetric  composition  given  in  the  gas  analysis 
yields  as  follows: 

22.10  cubic  feet  carbonic  acid 
i .  74  cubic  feet  carbonic  oxide 

14.20  cubic  feet  oxygen 
154. 10  cubic  feet  nitrogen 
192.14  cubic  feet  chimney  gases1 

1  The  sum  total  of  these  figures  for  the  volume  of  the  chimney  gas  is  192.14  cu. 
ft.,  which  is  surprisingly  close  to  the  figure  (193 . 7  cu.  ft.)  obtained  by  calculating  the 
amount  of  air  required,  from  the  chemical  composition  of  the  coal,  and  taking  into 
consideration  the  excess  of  air,  53.3  per  cent.,  as  found  by  the  formula  under  the  title 
"Pounds  of  air  per  pound  of  coal,"  already  explained. 


REGULATION    OF    COMBUSTION  91 

The  temperature  of  the  escaping  gases  was  527  deg. 
F.;  that  of  the  air  entering  the  grate,  77  deg.  F.,  a  rise 
of  temperature  of  450  deg.  F. :  the  specific  heats  (see 
page  29)  and  weights  of  a  cubic  foot  of  these  gases  are 
as  follows: 

Sp.  ht.  Weight  cu.  ft. 

Carbonic  acid 0.227  0.1234  Ib. 

Carbonic  oxide o'.245  0.0781 

Oxygen 0.217  0.0893 

Nitrogen o.  244  o.  0784 

Water  vapor 0.480  0.0500 

The  heat  carried  off  by  each  gas  is  its  weight  ( =  vol- 
ume X  weight  of  cubic  foot)  X  rise  of  temperature  X 
specific  heat;  that  is,  for 

Vol.        Weight      Rise     Sp.  ht.        B.t.u. 

Carbonic  acid ..22.1    Xo.  1234  X  450  X  0.227  =  278.6 

Carbonic  oxide. .  .......  1.74    X  0.0781  X  450  X  0.245  =  *5-o 

Oxygen 14.2    X  0.0893  X  450  X  0.217  =  I23-9 

Nitrogen 154.  i  X  0.0784  X  450  X  0.244  =  1326.6 

1744.1 

Besides  these  gases  there  is  another,  passing  up 
chimney  and  carrying  off  heat,  of  which  we  have  taken 
no  cognizance,  namely,  water  vapor  or  steam:  it  comes 
from  the  moisture  in  the  coal,  from  the  moisture  in  the 
air  which  burns  the  coal,  and  from  the  moisture  formed 
by  the  burning  of  the  hydrogen  contained  in  the  coal. 

The  moisture  in  the  coal  shown  by  the  analysis  is 
1.5  per  cent.  =0.015  Ib.;  the  hydrogen  in  the  coal  is 
2.5  per  cent.,  which,  when  burned,  gives  nine  times  its 
weight  of  water  =  0.025  X  9  =  0.225  Mb.  The  moist- 
ture  in  the  air  is  0.00085  Ib.  Per  cubic  foot  at  60  deg.  F., 
if  it  be  saturated;  it  was,  however,  only  half-satu- 


92  ENGINE-ROOM    CHEMISTRY 

rated,  =0.000425  Ib.  There  were  required  18  pounds 
of  air  per  pound  of  coal  (as  shown  in  the  calculation 
above,  under  "pounds  of  air  per  pound  of  coal")  or 
223  cu.  ft.  223  X  0.000425  =0.095  lb.  moisture  in  the 
air.  Total  moisture  =  o.oi 5  +0.225  +  0-095  =  °-335  lb. 
The  heat  carried  off  is  0.335  X  450  X  0.480  =  72.3 
B.t.u.,  and  the  total  heat  carried  off  is  1744.1  +72.3 
=  1816.4  B.t.u.  Heating  value  of  the  coal  by  the 
Mahler  bomb  is  13,000  B.t.u.  and  the  percentage  lost 

.     1816.4 

in  gases  is—       —  =  14.0  per  cent. 
13,000. 

The  foregoing  calculation  is  longer  and  even  more 
tiresome  than  the  former,  which  involved  the  calcula- 
tion of  the  pounds  of  air  per  pound  of  coal.  A  num- 
ber of  methods  have  been  proposed  which  give  results 
approximating  this  and  which  are  sufficiently  accu- 
rate for  technical  work.  The  formula 

ioo  -  %  CO2 
Loss  in  chimney  gases  =  (o.ou  -\ 0.0605)1'  —  t 

in  which  f  represents  the  temperature  in  the  chimney 
and  t  that  of  the  outside  air,  both  in  Centigrade  degrees, 
gives  close  results  and  is  independent  of  the  composi- 
tion of  the  coal:  applied  to  the  problem  in  question 
the  loss  comes  14.4  per  cent.,  or  0.4  per  cent,  higher 
than  by  the  other. 

Bunte  has  devised  the  chart  figured  below  (Fig.  27), 
which  enables  us  to  determine  the  loss  by  inspection. 
By  noting  the  point  at  which  the  diagonal  representing 
the  percentage  of  carbonic  acid  (CO2)  cuts  the  horizon- 
tal line  representing  the  actual  temperature  in  degrees 


REGULATION    OF    COMBUSTION 


93 


Fahrenheit,  and  dropping  a  perpendicular  from  this 
down  to  the  base-line,  the  percentage  of  heat  lost  is 
shown  on  the  base-line.  If  the  temperature  be  510 
deg.  F.  and  the  percentage  of  carbonic  acid  11.5,  we 
find  that  the  loss  is  about  17  per  cent.,  or  3  per  cent, 
higher  than  given  by  other  methods.  Tiiis  method 
gives  results  from  3  to  5  per  cent,  higher  than  the 
others. 


CO 


Per  Cent  Efficiency 
70 


100 


1G52 


1472 


Per  Cent  Loss 

FIG.  27.  —  Bunte's  Chart 

In  general  it  may  be  said  that  the  chimney  gases 
from  a  well-stoked  plant  should  contain  at  least  10  to 
12,  or  better  13  to  15  per  cent,  of  carbonic  acid  with 
practically  no  carbonic  oxide. 

Loss  due  to  the  formation  of  carbonic  oxide.  On  page 
89  we  notice  that  0.058  Ib.  of  carbon  burned  to  carbonic 
oxide:  for  every  pound  of  carbon  burned  to  carbonic 
oxide  there  is  a  loss  of  10,190  B.t.u.,  in  this  case,  a  loss 


94  ENGINE-ROOM    CHEMISTRY 

of  (10,190  X  0.058)  591  B.t.u.  The  heating  value  of  the 

coal  is  13,000  B.t.u.;  hence  the  loss  is— ^-  or  4.5  per 

1 3 ,000 

cent. 

Loss  due  to  unconsumed  carbon  or  coal  in  the  ashes. 
The  ashes  are  sampled  as  in  the  case  of  coal,  grinding 
them  in  the  iron  mortar,  and  the  percentage  of  moist- 
ure (if  any)  is  determined.  They  are  ignited  after  the 
manner  of  determining  ash  in  coal,  and  the  loss  is  fig- 
ured as  carbon.  Knowing  the  total  weight  of  ashes 
produced,  the  total  weight  of  carbon  in  them  can  be 
figured,  this  calculated  over  into  coal,  which,  divided 
by  the  weight  of  coal  fired,  gives  the  percentage  of  coal 
going  through  the  fire  unconsumed. 

B.     EXAMINATION    OF   CHIMNEY    GASES    BY    AUTO- 
MATIC APPARATUS 

These  depend  for  their  action  either  upon  the  con- 
tinuous weighing  of  a  changing  but  definite  volume  of 
chimney  gas,  as  in  the  "Econometer"  of  Arndt,1  or 
upon  the  continuous  weighing  a  globe  in  a  changing 
atmosphere  of  the  gas,  as  in  the  Gas  Balance  of  Cus- 
todis,  or  upon  the  laws  governing  the  flow  of  gases 
through  small  orifices,  as  in  the  Gas  "Composimeter" 
of  Uehling. 

Arndt's  Econometer.1— This  is  shown  in  Fig.  28.  It 
consists  of  a  counterpoised  vessel  18  through  which 
the  chimney  gases  are  caused  to  circulate:  the  per- 

1  Arndt  in  Aachen,  Germany,  has  devised  another  instrument  something  like 
Uehling's  called  the  ados,  "heating-effect-meter." 


REGULATION    OF    COMBUSTION 


95 


centages  of  carbonic  acid  contained  in  the  gases  are 
read  off  directly  from  the  index  on  the  scale  27  of  the 
balance. 

The  chimney  gases  are  drawn  continuously  by  the 
draft  in  the  chimney  itself  by  aspirator  67  from  the 
boiler  flue  61  first  through  a  gas  filter  56,  a  cotton  wool 


_jrO-mt         61 

Ql          J~~-*-  From  Boiler  Flu 
«7~\^ 


67 

FIG.  28. —  Arndt's  Econometer 

filter  5 1  to  remove  ashes  and  soot,  and  a  drying  tube 
45,  then  through  |-inch  tubing  and  fittings  42,  23,  19, 
etc.,  into  the  vessel  18  and  out  through  22,  62,  65,  etc., 
into  the  main  flue. 

The  following  table  shows  the  loss  of  heat  in  boilers 
by  the  indications  of  the  Arndt  Econometer,  using 
ordinary  coal: 


96  ENGINE-ROOM    CHEMISTRY 

PER  CENT.  CARBONIC  ACID 
2345        6       7       8       9      10     ii      12      13     14      15 

VOLUME  OF  AIR  MORE  THAN  THEORY 

9-5    6-3   4-7   3-8   3-2    2.7    2.4   2.1    1.9    1.7    1.6    1.5    1.4    1.3 
Theory  =  i .  o 

PER  CENT.  Loss  OF  HEAT  TEMP.  OF  CHIMNEY  GASES  518  DEC. 
90     60     45     36     30     26      23     20      18     16     15      14     13      12 


Air  lulet 


FIG.  29.  —  Custodis  Gas  Balance 

The  Custodis  Gas  Balance.  — This  is  shown  in  Fig.  29, 
and  is  practically  the  same  as  Arndt's  instrument  ex- 
cept that  where  the  latter  uses  a  balanced  globe  full  of 
chimney  gas,  in  a  chamber  of  air,  Custodis  uses  a  bal- 
anced globe  of  air  in  a  chamber  of  chimney  gas. 


REGULATION    OF    COMBUSTION 


97 


In  the  figure  k  and  /  are  the  balanced  globes,  and  / 
the  chamber  (at  the  right)  into  which  the  chimney  gas 
is  sucked  through,  just  as  in  the  previous  case,  the  gas 
being  filtered  but  not  dried;  the  percentage  of  carbonic 
acid  is  read  off  on  the  scale  n;  a  gentle  current  of  air  is 
caused  to  circulate  through  e,  the  chamber  (at  the  left) 
in  which  the  globe  k  hangs.  . 

Uehling's  Gas  Composimeter  is  shown  diagrammati- 
cally  in  Fig.  30  and  as  actually  built  in  Fig.  31.  As 


FIG.    30.  —  Uehling's  Gas  Composimeter. 
Diagram 

stated  above,  it  is  based  on  the  laws  governing  the 
flow  of  gases  through  small  apertures. 

If  two  such  apertures,  A  and  B  (Fig.  30)  form  re- 
spectively the  inlet  and  outlet  openings  of  chamber  C 
and  a  uniform  suction  is  maintained  in  the  small  cham- 
ber O  at  the  left  by  the  aspirator  D,  the  action  will  be 
as  follows: 

Gas  will  be  drawn  through  the  aperture  B  into  the 
chamber  O,  creating  suction  in  chamber  C,  which,  in 


98 


ENGINE-ROOM    CHEMISTRY 


turn,  causes  gas  to  flow  through  the  aperture  A.    The 
velocity  with  which  the  gas  enters  through  A  depends 


FIG.  31.  —  Uehling's  Gas  Composimeter 

on  the  suction  in   the  chamber  C,  and  the  velocity 
with  which    it    flows  out    through  B  depends   upon 


REGULATION    OF    COMBUSTION  99 

the  excess  of  the  suction  in  chamber  C  over  that  ex- 
isting in  chamber  C;  that  is,  the  effective  suction  in 
C.  As  the  suction  in  C  increases,  the  effective  suc- 
tion must  decrease,  and  hence  the  velocity  of  the  gas 
entering  at  A  increases,  while  the  velocity  of  the  gas 
passing  out  through  B  decreases,  until  the  same  quan- 
tity of  gas  enters  at  A  as  passes  out  at  B.  As  soon  as 
this  occurs  no  further  change  of  suction  takes  place  in 
the  chamber  C,  providing  the  gas  entering  at  A  and 
passing  out  at  B  be  maintained  at  the  same  tempera- 
ture. 

If,  from  the  constant  stream  of  gas  while  flowing 
through  chamber  C,  one  of  its  constituents  is  continu- 
ously removed  by  absorption,  a  reduction  of  volume 
will  take  place  in  chamber  C  and  cause  an  increase  in 
suction  and  consequently  a  decrease  in  the  effective 
suction  in  C.  Hence  the  velocity  of  the  gas  through 
A  will  increase  and  the  velocity  through  B  will  de- 
crease until  the  same  quantity  of  gas  enters  at  A  as  is 
absorbed  by  the  reagent,  plus  that  which  passes  out  at 
aperture  B. 

Thus  every  change  in  the  volume  of  the  constituents 
we  are  absorbing  from  the  gas  causes  a  corresponding 
change  of  suction  in  the  chamber  C. 

If  the  manometer  tubes  p  and  q  (Fig.  30)  com- 
municate respectively  with  the  chambers  C  and  O, 
the  column  in  the  tube  q  indicates  the  constant  suc- 
tion in  C,  and  the  column  in  tube  p  indicates  the 
suction  in  C',  which  suction  is  a  true  measure  of  the 
percentage  of  the  constituent  we  wish  to  measure  in 
the  gas. 


loo  ENGINE-ROOM    CHEMISTRY 

PRACTICAL    APPLICATION    OF    THE     PRINCIPLE     OF     THE 
GAS    COMPOSIMETER 

To  embody  the  principles  described  in  a  practical 
apparatus,  the  following  conditions  must  be  fulfilled: 

a.  The  gas  must  be  brought  to  the  instrument  under 
a  constant  tension  and  must  be  drawn   through   the 
apertures  with   a  continuous   and   perfectly  uniform 
suction. 

b.  Both  apertures  must  be  located  in  a  medium  of 
constant  temperature. 

c.  Provision  must  be  made  that  the  apertures  re- 
main perfectly  clean. 

d.  The  chamber  C  must  be  made  perfectly  tight  so 
that  no  gas  can  enter  except  through  the  aperture  A. 

e.  Provision  must  be  made  to  render  the  gas  free 
from  moisture. 

/.  The  constituent  to  be  measured  must  be  com- 
pletely absorbed  after  the  gas  passes  through  A  and 
before  it  passes  out  at  B. 

Fig.  31  shows  the  apparatus  as  actually  constructed. 
C  is  the  regulator  insuring  a  constant  suction.  O  is 
that  portion  of  the  apparatus  which  contains  apertures 
A  and  B  (Fig.  30),  and  which  is  kept  at  the  constant 
temperature  of  steam  at  atmospheric  pressure.  E  and 
E'  are  saturators  through  which  the  gas  passes,  re- 
spectively, before  entering  A  and  before  entering  B, 
thus  insuring  the  same  quantity  of  moisture  in  the  gas 
at  both  A  and  B.  F  contains  the  absorbent  and  is  sit- 
uated between  the  two  apertures.  5  is  the  scale  from 
which  the  percentage  of  CO2  can  be  read  at  will,  while 


REGULATION    OF    COMBUSTION  101 

G  is  the  gage  which  makes  a  continuous  record  of  the 
same.  M  is  the  reservoir  which  supplies  F  with  the 
absorbent,  while  N  is  the  receiver  for  this  solution  after 
it  has  been  used. 

In  general  these  apparatus  are  difficult  to  adjust 
and  to  keep  in  adjustment,  requiring  checking  by  the 
gas  analytical  apparatus;  yet  it  is  said  that  the  Uehling 
Gas  Composimeter  has  recently  been  developed  into  a 
very  practical  instrument,  which  can  be  used  continu- 
ously and  which  needs  very  little  attention.  Their 
indications  are  within  about  0.5  per  cent,  of  those  given 
by  the  chemical  apparatus.  Only  the  presence  of  car- 
bonic acid  is  indicated  by  them. 


BOILER   SCALE  —  PITTING   AND   CORROSION 

THE  troubles  indicated  in  the  title  of  this  chapter 
spring  mainly  from  one  source,  impure  or  "hard" 
water,  although  very  pure  and  soft  water  may  also 
cause  corrosion. 

Hard  water  may  be  defined  as  water  containing  in 
solution  mineral  compounds  that  curdle  or  precipitate 
soap.  Under  this  definition  are  included  the  saline 
waters,  as  sea-water  and  some  of  the  alkali  waters  of 
the  West,  as  well  as  those  usually  called  "hard." 
The  substances  which  render  water  hard  are  salts  of 
lime,  magnesia,  and  iron,  which  are  held  in  solution  1 
in  cold  water  and  precipitated  on  boiling.  These  salts 
are  usually  either  carbonates  or  sulphates,  and  are 
precipitated  for  different  reasons:  the  carbonates  are 
held  in  solution  by  the  carbonic  acid  which  the  water 
absorbs  in  falling  through  the  atmosphere  and  passing 
through  the  earth.  Water  containing  carbonic  acid 
dissolves  the  carbonates  of  the  bases  named,  so  that 

1  Care  should  be  taken  to  note  the  distinction  between  "solution"  and  "suspen- 
sion" as  defined  on  p.  2,  footnote.  Solution  is  exemplified  by  the  mixing  of  water 
and  salt  so  that  the  latter  disappears  or  dissolves  and  cannot  be  separated  by  filtering 
through  paper.  Suspension  is  shown  in  the  mingling  of  water  and  clay,  the  latter 
separating  from  the  water  on  standing  a  sufficient  length  of  time. 


PITTING    AND    CORROSION  103 

they  exist  there  really  as  bicarbonates.  On  the  re- 
moval of  the  carbonic  acid,  either  by  chemical  agents 
or  by  boiling,  the  carbonates  are  precipitated.  "Sul- 
phate of  lime"  or  calcium  sulphate  is,  contrary  to  the 
usual  experience,  more  insoluble  in  hot  water  than  in 
cold;  consequently  when  water  containing  it  is  heated, 
it  is  thrown  down,  and  completely  so,  at  a  pressure  of 
35  pounds. 

Magnesium  compounds,  except  the  carbonate,  are 
soluble,  and  are  usually  not  precipitated;  the  state- 
ment, however,  is  made  that  magnesium  sulphate 
forms  scale  in  the  presence  of  calcium  carbonate. 
Magnesium  chloride  is  decomposed  at  temperatures  a 
little  above  the  boiling-point  of  water  into  hydrochloric 
acid  and  magnesia.  The  hydrochloric  acid  dissolves 
any  scale,  converting  it  into  calcium  chloride.  The 
magnesia,  coming  in  contact  with  any  soda  ash  used 
in  softening  the  water,  changes  it  over  to  caustic  soda, 
which  combines  with  any  carbonic  acid  that  happens 
to  be  present. 

Magnesium  chloride + hydrogen  oxide     =  hydrogen  chloride 

+  magnesium 

oxide 

(water)          (hydrochloric  acid)  (magnesia) 
MgCl2  +          H20  =       2HC1         +      MgO 

Calcium  carbonate   +  hydrogen  chloride  =  calcium  chloride 

+  hydrogen 

carbonate 

Chalky  boiler  scale         (muriatic  acid)      (carbonic  acid  +  water) 
CaC03  +  2HC1  =       CaCl2        +^03 

(  =  H20  +  C02) 


104  ENGINE-ROOM    CHEMISTRY 

Magnesium  oxide      +  sodium  carbonate  =  sodium  oxide 


(Magnesia) 
MgO 

Sodium  oxide 


(soda  ash) 
Na2C03 


Na20 


+  magnesium 
carbonate 

+    MgC03 


Sodium  hydrate 
2NaOH 


+  water 
+  H20 


+  carbonic  acid 


CO, 


sodium  hydrate 
sNaOH 

sodium  carbonate 

+  water 


Na2CO3 


H2O 


Hardness,  due  to  the  bicarbonates,  which  is  lessened 
by  boiling,  is  said  to  be  "temporary,"  while  that  which 
is  not  removed  in  this  way  is  said  to  be  "permanent." 
Low  hardness,  to  200  parts  of  calcium  carbonate 
per  million,  is  usually  determined  by  means  of  a  stand- 
ard solution  of  soap.  To  this  end  50  cubic  centimeters 
of  the  water  are  measured  into  a  tall  2oo-cc.  clear-glass 
bottle;  alcoholic  soap  solution  is  added  to  it  from  a 
burette,  shaking  well  after  each  addition,  until  a  lather 
is  obtained  which  covers  the  entire  surface  of  the  liquid, 
with  the  bottle  lying  on  its  side,  and  is  permanent  for 
five  minutes.  From  the  number  of  cubic  centimeters 
of  soap  solution  used  the  hardness  of  the  water  may 
be  calculated  by  the  use  of  Clark's  table  below:  it  is 
usually  reported  in  this  country  l  in  parts  of  calcium 
carbonate  (CaCO3)  per  million. 

1  Also  in  France.  In  England  a  degree  of  hardness  means  one  grain  of  calcium 
carbonate  per  imperial  gallon;  in  Germany,  one  part  of  calcium  oxide  (CaO)  per 
hundred  thousand.  To  convert  grains  per  gallon  to  parts  per  million  multiply  by 
17.18. 


PITTING    AND    CORROSION 

CLARK'S  TABLE  OF  HARDNESS 


Cc.  soap  sol. 

Pts.  CaCO3 
per  million 

Cc.  soap 

Pts. 
CaC03 

Cc.  soap 

Pts. 
CaCO3 

0.7 

o.o 

6.0 

74.0 

12.0 

164.0 

1.0 

5-o 

7.0    • 

89.0 

13.0 

180.0 

2.0 

19.0 

8.0 

103.0 

14.0 

196.0 

3-° 

32.0 

9.0 

118.0 

15.0 

2I2.O 

4.0 

46.0 

10.0 

i33-° 

5-° 

60.0 

II.O 

148.0 

If,  for  example,  8  cc.  soap  solution  were  required,  it 
signifies  that  the  mineral  compounds  in  the  water  pro- 
duce a  degree  of  hardness  in  the  water  equivalent  to 
that  which  would  be  produced  by  103  parts  of  calcium 
carbonate  (CaCO3,  chalk)  in  one  million  parts  of  water. 

For  waters  which  are  harder  than  200  parts  per  mil- 
lion, a  solution  of  soap  ten  times  as  strong  may  be  used, 
the  end  point  being  taken  at  the  time  when  sufficient 
soap  has  been  added  to  deaden  the  harsh  sound  pro- 
duced on  shaking  the  bottle  containing  the  water.1 

The  standard  soap  solution  can  be  obtained  from 
dealers  in  fine  chemicals  and  apparatus,  or  from  an 
analytical  chemist.  (The  other  methods  of  determin- 
ing hardness,  "temporary"  by  means  of  hydrochloric 
acid  (Hehner's  method),  "permanent,"  by  sodium  car- 
bonate and  hydrate  (Pfeifer  and  Wartha's  method), 
and  magnesia  by  lime-water  (Pfeifer 's  method),  require 
the  services  of  a  skilled  chemist.) 


1  See  paper  by  C.  R.  Walker  in  Tech.  Quarterly,  xvii,  281. 


106  ENGINE-ROOM    CHEMISTRY 

This  determination  of  hardness  by  soap  test  enables 
us  to  estimate  what  quantity  of  soda  crystals  to  use  in 
softening  the  water;  but  without  a  chemical  analysis 
it  is  impossible  to  calculate  exactly  how  much  will  be 
required,  since  we  do  not  know  how  much  calcium  sul- 
phate (CaSOJ  there  may  be,  or  whether  magnesium 
salts  are  present.  In  any  event  the  water  will  prob- 
ably be  left  slightly  hard. 

If  the  soap  test  indicates  there  are  103  pounds  of 
calcium  carbonate  in  one  million  pounds  of  water,  as 
in  the  example  just  cited,  the  estimate  of  the  quantity 
of  soda  crystals  required  is  made  by  means  of  the 
formula, 

soda  crystals  :  calcium  carbonate  : :  weight  soda  crystals  :  weight 
calcium  carbonate, 

or,  chemically  expressed, 

(Na2CO3  +  ioH2O)  :  CaCO3  :  :  x  :  103 

soda  crystals        :  calcium  carbonate 

2  X  23  +  12  +  (3  X  1 6)  +  10  X  (2  +  1 6)  :  40  +  12  +  48  ::  x  :  103 
286  100  ::  x :  103 

whence  x  =  294  Ib.  soda  crystals  per  million  pounds  water,  or  120,000 
gallons,  =  2.45  Ib.  per  thousand  gallons. 

If  the  calculation  be  desired  where  soda  ash,  or  dry 
soda  crystals,  is  to  be  used,  it  is  as  follows: 

Na2CO3  =  (2  X  23)  +  12  +  (3  X  16)  =  106  :  28.6  ::y:  2.45 
y  =  0.91  Ib.  soda  ash  per  1000  gallons. 

Expressing  this  in  the  form  of  a  rule  it  reads  thus: 
To  determine  the  number  of  pounds  of  soda  crystals 
required  per  thousand  gallons  of  water,  multiply  the 


PITTING    AND    CORROSION  107 

hardness  expressed  in  parts  of  calcium  carbonate  per 
million  by  the  factor  0.0238:  the  quantity  of  soda  ash  is 
found  by  multiplying  by  the  factor  0.00883.  While  the 
amount  thus  obtained  by  calculation  is  theoretically 
correct,  experience  shows  that  it  is  excessive,  and  that 
only  about  one-quarter  of  this  quantity  is  actually 
needed. 

Effects  of  Hard  Water. — The  effects  of  hard  water 
are: 

1.  The  production  of  scale  with  its  accompanying 
losses. 

2.  The  corrosion  of  the  boiler  shell. 

3.  The  causing  of  foaming  in  the  boilers. 

i.  The  production  of  scale  causes  (a)  Waste  of 
fuel;  (b)  Expense  in  removing;  (c)  Burning  out  of 
crown  sheets  and  corrosion  of  the  boiler  shell. 

(a)  Waste  of  fuel.  Scale  being  a  poorer  conductor 
of  heat  than  iron,  it  retards  the  transference  of  heat 
from  the  metal  to  the  water:  the  approximate  loss  is 
as  follows: 

Thickness  of  scale  Loss  of  heat 

in  inches  per  cent. 

&  13-16 

i  38-50 

£  60-150 

This  means  that  the  scale  one-sixteenth  of  an  inch 
thick  causes  a  loss  of  heat  of  about  16  per  cent.,  or 
one-seventh  of  the  coal  fired.  Scale,  however,  is  not 
always  a  detriment.  In  some  cases  it  serves  to  pre- 
vent general  corrosion.  In  using  a  very  pure  natural 
water  containing  much  carbonic  acid,  as  Loch  Katrine 


lo8  ENGINE-ROOM    CHEMISTRY 

water,  it  is  recommended  to  cover  the  inside  of  the 
boiler  with  a  scale  1-50  in.  thick.  With  marine  boilers, 
a  mixture  of  milk  of  magnesia  and  gypsum  is  added  to 
the  feed-water  for  this  same  purpose. 

(b)  Removal  of  scale.     Boiler  scale  is  of  two  vari- 
eties: (i)  a  hard,  crystalline,  adherent  scale  which  is 
due  to  the  presence  of  calcium  sulphate:  originally 
precipitated  as  a  powder,  it  is  changed  over  into  the 
crystalline  form  by  heat.     This  serves  as  a  binding 
material  for  any  precipitate  in  the  water,  as  calcium 
or  magnesium  carbonate,  iron  rust,  clay,  mud,  or  sand. 
(2)  A  soft,  powdery,  scale  due  to  the  precipitated  car- 
bonates and  the  materials  just  mentioned.     The  soft 
scale  may  be  removed  by  blowing  off  the  boiler,  first 
using  the  scum  cocks,  and  washing  out  the  powder  with 
a  hose  stream.     For  removing  adherent  scale,  kerosene 
has  given  good  results  in  some  cases:  the  oil  floats  on 
the  surface  of  the  water,  penetrates  the  scale  as  the 
boiler  is  blown  off,  and  upon  firing  up  again  the  expan- 
sion of  the  kerosene  vapor  causes  the  scale  to  crack  off 
from  the  places  to  which  it  adheres  and  enables  it  to 
be  removed  by  blowing  off.     The  use  of  various  acids 

-  hydrochloric,  acetic,  or  even  tannic  —  is  not  to  be 
recommended,  as  they  attack  not  only  the  scale,  but 
also  the  boiler  itself.  A  hard,  firmly  adherent  scale 
can  only  be  removed  by  a  hammer  and  chisel. 

(c)  Burning  out  of  the  crown  sheets  and  corrosion 
of  the  boiler  shell.     To  transmit  the  same  quantity  of 
heat,  a  crown  sheet  covered  with  scale  has  to  be  heated 
to  a  higher  temperature  than  a  clean  one,  causing  a 
burning  or  oxidation  of  the  iron.     To  a  similar  cause 


PITTING    AND    CORROSION  109 

is  due  the  corrosion  or  pitting  upon  the  inside  of  these 
sheets.  Particles  of  cylinder  oil  floating  on  the  top  of 
the  water  in  the  boiler  become  loaded  with  scum,  sink 
to  the  bottom  and  adhere  to  it,  acting  like  scale  and 
preventing  the  transmission  of  heat.  The  sheet  be- 
neath them  gets  sufficiently  hot  to  char  and  decom- 
pose the  oil,  loosening  it  and  allowing  the  water  to 
come  in  contact  with  the  red-hot  iron;  this  gives  rise 
to  a  sudden  evolution  of  steam  and  may  cause  an  ex- 
plosion, and  in  any  case  attacks  the  plate,  forming  a 
rust  on  the  inside  of  the  boiler  shell. 

Iron  +  hydrogen  oxide  =  iron  oxide  +  hydrogen 

(water) 
3Fe  +          4H2O  =       Fe3O4      +        4H2 

2.  The  corrosion  of  the  boiler  shell.  This  has  already 
been  partly  treated  of  in  the  foregoing  paragraph. 
Corrosion  is  also  due  to  organic  matters  or  acids  con- 
tained in  natural  waters,  particularly  those  from 
swampy  districts:  these  may  contain  tannic,  humic, 
and  carbonic  acids  which  dissolve  iron.  Waters  from 
mining  districts  are  apt  to  contain  mineral  acids,  par- 
ticularly sulphuric  from  the  oxidation  of  pyrites  or 
other  sulphur-containing  ores.  Polluted  water  con- 
taining salt,  chlorides  of  calcium  or  magnesium  and 
nitrates  are  also  strongly  corrosive.  These  produce 
general  corrosion — a  weakening  of  the  shell.  Fig.  32 
from  Peabody  and  Miller,  "Steam  Boilers,"  illustrates 
this  well;  it  shows  the  protection  of  the  plate  by  the 
rivet  head. 

Corrosion  of  steam  pipes,  particularly  "returns," 
seems  to  be  due  mainly  to  carbonic  acid  and  oxygen 


HO  ENGINE-ROOM    CHEMISTRY 

contained  in  the  water,  a  small  amount  of  carbonic 
acid  dissolving  an  unlimited  quantity  of  iron,1  the  pro- 
cess being  a  cyclic  one.  The  carbonic  acid  driven 
off  from  the  water  in  the  boiler,  goes  with  the  water 
vapor  and  steam  to  the  cooler  part  of  the  system,  where 
it  dissolves  in  the  condensed  steam  and  attacks  the 
iron  pipes  with  which  it  comes  in  contact. 

Iron  +  carbonic  acid  =  bicarbonate  of  iron  +  hydrogen2 
Fe    +       2H2C03       -         FeH2(COa)2        +         H2 

This  bicarbonate  of  iron  when  it  meets  the  heated  part 
of  the  return  pipes  or  gets  into  the  boiler  itself  is  de- 


FIG.  32. —  General  Corrosion 

composed,  giving  oxide  of  iron  or  iron,  rust  and  setting 
free  the  carbonic  acid  which  promptly  renews  the  at- 
tack. 

Bicarbonate  of  iron  =  ferrous  oxide  +  water  +  carbonic  acid 

FeH2(CO3)2         =          FeO         +   H2O  +         2CO2 

Ferrous  oxide  +  oxygen  =  ferric  oxide 

2  FeO         +       O      =       Fe2O3 

As  indicative  of  the  effect  of  water  containing  carbonic 

1  This  has  been  shown  by  Whitney,  in  Journal  American  Chemical  Society,  xxv 
(1903),  394- 

2  The  gas  often  found  in  hot-water  radiators  is  mainly  hydrogen. 


PITTING    AND    CORROSION  in 

acid  upon  iron,  the  case  may  be  cited  of  the  corrosion 
of  a  stay  within  a  boiler,  produced  by  the  discharge 
upon  it  of  the  cold  feed-water  containing  carbonic  acid. 
The  remedy  for  this  carbonic  acid  corrosion  consists 
in  adding  caustic  soda,  or,  better,  lime-water,  to  the 
feed-water.  The  quantity  can  be  calculated  as  fol- 
lows: water  at  ordinary  temperatures  dissolves  its 
own  volume  of  carbonic  acid;  that  is,  every  gallon  of 
water  carries  in  23 1  cubic  inches  of  carbonic  acid.  One 
cubic  inch  of  carbonic  acid  weighs  11.55  grains;  the 
equation  representing  the  reaction  between  caustic 
soda  and  carbonic  acid  is 

sodium  hydrate  +  carbonic  acid  =  sodium  carbonate  4-  water 
2NaOH         +          CO2  Na2CO3          +  H2O 

2  (23  +  16  +  i)  :  (12  +  32)  ::  x  :  11.55.     x  =  2O-9  grains 
80  :        44 

of  caustic  soda  per  gallon,  or  three  pounds  to  the  thou- 
sand gallons.  To  determine  the  amount  of ,  slaked 
lime  we  can  make  the  proportion 

lime     :  caustic  soda  : :  y  .-3 
CaO2H2 :  2NaOH 

74      :       80  y  =  2 . 8  pounds. 

2 . 8  pounds  of  slaked  lime  per  thousand  gallons. 

Pitting,  the  term  applied  to  local  corrosion,  may  be 
formed  by  oil  drops,  as  above  indicated,  or  by  the  in- 
troduction of  iron  scale  (forge  scale),  coke,  chips  of 
brass  or  copper  into  the  boiler:  these  are  all  electro- 
negative to  the  iron,  cause  a  galvanic  action  between 
themselves  and  the  iron  of  the  boiler,  with  the  usual 
result  that  the  positive  metal  is  dissolved  —  in  this 
case  the  iron.  Pitting  may  also  be  due  to  the  fact  that 


112  ENGINE-ROOM    CHEMISTRY 

the  boiler  plates  are  not  homogeneous.  Fig.  33,  also 
from  Peabody  and  Miller,  shows  pitting  at  the  corner 
of  a  flanged  plate. 

This  pitting  may  be  prevented  by  the  introduction 
into  the  boiler  of  plates  of  zinc,  a  metal  more  positive 
than  iron,  which  is  dissolved  in  its  place;  this  is  fre- 
quently done  with  marine  boilers. 

It  is  not  sufficient  to  hang  zinc  slabs  in  the  boiler, 
or  throw  them  in.  They  must  be  bolted  on  to  projec- 
tions from  the  boiler  itself,  making  good  electrical  con- 


FIG.  33.  —  Pitting  of  Iron 

tact.  For  new  boilers  allow  one  square  foot  of  zinc 
to  each  50  feet  of  heating  surface,  and  later  half  this 
amount. 

Another  source  of  pitting  or  corrosion  of  boilers, 
formerly  of  more  frequent  occurrence  than  at  the 
present  time,  is  the  presence  of  animal  or  vegetable  oils 
coming  from  cylinder  lubrication.  These  were  for- 
merly used  in  a  pure  condition  for  this  purpose:  now 
cylinder  oil  does  not  usually  contain  more  than  5  or  7 
per  cent,  of  these  oils,  the  remainder  being  mineral  oil. 
This  small  quantity  is  probably  without  appreciable 


PITTING    AND    CORROSION  113 

action  upon  the  boiler.  Whenever  animal  or  vege- 
table oils  are  heated  together  with  steam  at  high 
pressure,  they  are  decomposed  with  the  formation  of 
glycerin  and  fatty  acids  —  stearic,  palmitic,  oleic,  and 
others.  These  acids  at  the  high  temperature  .attack 
the  metals  with  which  they  come  in  contact.  They 
are  also"  one  of  the  causes  of  the  pitting  of  cylinders. 

Glyceryl  stearate  +  water  =  glyceryl  hydrate  +  stearic  acid 
tallow  glycerin 

Besides  the  causes  of  corrosion  already  considered, 
namely,  (a)  the  high  temperatures  of  the  crown  sheets, 

(b)  the  presence  of  bodies  electronegative  to  the  iron, 
as  forge  scale,  cinders  or  coke,  copper  or  brass  chips, 

(c)  animal  oils,  (d)  acids,  acetic,  tannic,  humic,  sul- 
phurous or  sulphuric,  and   (e)  polluted  or  sea-water 
containing  nitrates  and  chlorides,  the  following  corrod- 
ing agencies  may  be  noticed:  (/)  alkaline  substances, 
as   caustic   soda   and   lime-water.     These   have   little 
action  upon  iron  but  attack  copper  or  brass  fittings 
vigorously,     (g)  Strains  upon  iron.     If  iron  be  under 
strain  this  has  a  tendency  to  open  the  pores  of  the 
metal,  admitting  water  and  carbonic  acid  and  increas- 
ing the  oxidation  of  the  iron,     (h)  The  escape  of  a 
stream  of  water  in  a  fine  jet  from  a  boiler  seam  may 
cause  corrosion,  from  the  continuous  removal  of  the 
oxide  of  iron  produced  by  the  action  of  the  water  upon 
the  iron. 

3.  The  causing  of  foaming  or  priming  in  the  boilers. 
This  is  most  likely  due  to  the  precipitation  of  the  scale- 
forming  matter  as  a  fine  powder:  these  particles  serve 
as  points  from  which  steam  is  liberated.  This  is  a 


H4  ENGINE-ROOM    CHEMISTRY 

well-known  fact  and  is  taken  advantage  of  by  the  chem- 
ist in  boiling  solutions  which  have  a  tendency  to 
"bump,"  as  the  expression  is;  that  is,  they,  after  boil- 
ing for  a  time,  suddenly  become  quiet  for  a  few  seconds, 
and  with  equal  suddenness  boil  explosively  over  the 
entire  surface,  causing  the  liquid  to  run  over.  By  the 
addition  of  a  few  pieces  of  ignited  and  quenched  pum- 
ice-stone or  bits  of  platinum-foil,  the  boiling  proceeds 
regularly,  currents  of  steam  being  seen  to  rise  from 
them.  This  foaming  can  be  shown  by  boiling  a  mix- 
ture of  alcohol  and  water  in  a  flask,  when  the  boiling 
suddenly  stops,  and  if  the  heating  be  continued  the 
liquid  becomes  superheated:  if  the  lamp  be  now  re- 
moved and  sand  scattered  into  the  flask  it  will  almost 
empty  itself  by  the  violence  of  the  boiling. 

This  foaming  is  seen  less  frequently  with  stationary 
boilers  than  with  locomotives,  for  the  reason  that  the 
feed-water  is  practically  the  same  in  the  former  case. 
In  the  latter  case  this  trouble  manifests  itself  in  the 
West,  where  after  using  a  hard  water  it  is  followed  by 
that  of  the  alkali  belt:  the  alkali  precipitates  the  lime 
and  magnesia  as  carbonates  from  the  hard  water,  in  a 
finely  divided  condition,  causing  the  foaming  in  the 
manner  indicated  above. 

Remedies  for  Hard  Water.  —  As  to  boiler  compounds. 
J.  M.  Boon  expresses  the  opinion  that  "The  only  com- 
pound to  put  into  a  boiler  is  pure  water."  It  has  been 
estimated  that  the  actual  cost,  that  is  waste,  of  fuel, 
repairs,  etc.,  due  to  hard  water  and  boiler  scale  is  about 
1750  per  year  for  each  locomotive  in  the  United  States. 
While  in  the  case  of  stationary  boilers  no  such  figures 


PITTING    AND    CORROSION  115 

are  available,  it  may  be  said  in  a  general  way  that  the 
life  of  the  boiler  would  be  increased  threefold  by  the 
use  of  soft  water,  to  say  nothing  of  the  gain  accruing 
from  continuous  service. 

Almost  everything  under  the  sun  1  has  been  pro- 
posed for  the  removal  of  boiler  scale  and  softening  of 
water,  including  potato  parings,  molasses,  and  tan- 
bark.  The  last  two  act  by  virtue  of  the  acids  which 
they  contain,  the  one  acetic  and  the  other  tannic; 
these  may  act  on  the  scale  precipitated,  but  they  cor- 
rode the  shell  of  the  boiler. 

While  the  proper  place  for  the  treatment  of  water  is 
outside  the  boiler,  yet  many  prefer,  on  account  of  con- 
venience, lack  of  room,  or  other  causes,  to  soften  the 
water  in  the  boiler  itself,  and  it  is  a  question  of  the  most 
suitable  compound  to  employ.  A  proper  substance  is 
one  that  precipitates  the  salts  which  make  water  hard, 
in  a  powdery  or  flocculent  condition  so  that  they  can 
be  easily  blown  out.  It  should  not  be  acid  nor  yield 
up  acid  on  treatment.  It  should  be  cheap  and  easily 
applied.  Salts  of  sodium  (calcium  or  lime)  fulfil  all 
these  conditions  and  are  usually  employed.  Let  us 
now  see  the  action  of  some  of  the  various  compounds 
proposed. 

Caustic  soda  or  caustic  lime  (lime-water).  These 
combine  with  the  carbonic  acid  contained  in  the  water 
in  combination  as  bicarbonates,  and,  as  this  acid  holds 
the  calcium  and  magnesium  carbonates  in  solution 
they  are  precipitated.  Another  action  is  to  combine 

1  For  a  list  of  these,  some  170  in  all,  see  Davis,  "Steam  Boiler  Incrustation  and 
Corrosion,"  page  72. 


n6  ENGINE-ROOM    CHEMISTRY 

with  any  acid  —  sulphuric  from  mines,  carbonic  from 
the  air,  tannic  or  humic  acid   from   swampy  waters. 

Lime-water  +  carbonic  acid  =  calcium  cabonate  +  water 
CaO2H,>     +          CO2  CaCO3  +  H2O 

Caustic  soda  +  tannic  acid  =  sodium  tannate  +  water 
NaOH       +   HCi4H900  =      NaCi4H9O9      +  HaO 

Soda  ask  or  sodium  carbonate.  This  acts  on  the  bi- 
carbonates  of  lime  or  magnesia,  forming  bicarbonate  of 
soda,  which  is  decomposed  by  the  temperatures  in  the 
boiler  into  carbonic  acid  and  sodium  carbonate.  Un- 
less magnesium  chloride  be  present,  decomposing  as 
has  been  shown  into  the  oxide,  carbonate  of  soda  has 
no  power,  unless  in  the  cold,  of  fixing  carbonic  acid  - 
caustic  soda  or  lime  ("lime-water")  is  required  for  this. 
It  transforms  the  sulphates  into  carbonates^  changing 
what  would  be  a  hard,  crystalline,  adherent  scale  of 
gypsum  into  the  powdery  calcium  carbonate  which  is 
easily  blown  out.  The  precipitation  of  these  carbon- 
ates has  a  tendency  to  clarify  the  water  if  it  contains 
clay  or  mud,  not,  however,  to  the  extent  to  which  a 
more  flocculent  precipitate  does.  It  neutralizes  acids, 
as  does  caustic  soda,  with,  however,  the  liberation  of 
carbonic  acid.  It  is  often  used  in  connection  with 
lime-water  to  soften  hard  water,  its  object  being  to 
precipitate  the  excess  of  lime  used. 

Calcium  bicarbonate  +  sodium  carbonate  =  sodium  bicarbonate  + 
CaH2(CO3)2          +  Na2CO3  2NaHCO3          + 

calcium  carbonate 
CaC03 

This  on  being  boiled  gives  sodium  carbonate  and  car- 
bonic acid 


PITTING    AND    CORROSION  117 

sodium  bicarbonate  =  sodium  carbonate  +  water  +  carbonic  acid 

2NaHC03  Na2C03          +  H2O  +          CO2 

calcium  sulphate  +  sodium  carbonate  =  calcium  carbonate  + 
CaS04  +  Na2COa  CaCO3  + 

sodium  sulphate 

Na2S04 

sulphuric  acid  +  sodium  carbonate  =  sodium  sulphate  + 
H2SO4         +  Na2CO3     '     =         Na2SO4         + 

carbonic  acid  +  water 
(H2CO3)CO2  +  H2O 

Sodium  aluminate,  made  by  fusing  soda  ash  and 
alumina  together,  may,  for  practical  purposes,  be  re- 
garded as  acting  like  caustic  soda.  In  addition  to  the 
advantages  enumerated  for  caustic  soda,  it  has  an- 
other, that  aluminum  hydrate  is  thrown  down  as  a 
light,  flocculent  precipitate,  which  possesses  to  a 
marked  degree  the  property  of  clarifying  waters; 
hence  it  should  carry  down  not  only  the  carbonates 
of  lime  and  magnesia1,  but  organic  matter,  as  humic 
acid,  tannic  acid,  clay,  mud  and  sand  in  such  a  condi- 
tion that  they  could  be  easily  removed  by  blow- 
ing off. 

Sodium  aluminate  +  calcium  bicarbonate  +  water  = 
Na2Al2O4          +         CaH2(CO3)2         +  2H2O  = 

sodium  carbonate  +  aluminum  hydrate     +  calcium  carbonate 
Na2CO3          +  2A1O3H3  +  CaCO3 

Sodium  fluoride.  When  sodium  fluoride  is  added  to 
water  containing  calcium  bicarbonate,  the  water  is 
rendered  soft,  calcium  fluoride  and  sodium  bicarbo- 
nate being  formed. 


Ii8  ENGINE-ROOM    CHEMISTRY 

Calcium  bicarbonate  +  sodium  fluoride  =  sodium  bicarbonate  + 
CaH2(CO3)2         +  2NaF  2NaHCO3         + 

calcium  fluoride  (fluorspar) 
CaF2 

A  similar  interchange  takes  place  with  calcium  sul- 
phate, or  the  corresponding  magnesium  compounds. 
Calcium  fluoride  is  precipitated  as  a  powder,  and  is 
about  twice  as  soluble  in  water  as  calcium  carbonate, 
one  part  dissolving/  in  about  26,000  parts  of  water, 
whereas  50,000  parts  are  required  to  dissolve  the  car- 
bonate. Sodium  fluoride  is  claimed  not  to  attack 
valve  metal  nor  iron,  nor  to  cause  foaming  and  to  take 
up  oil. 

Trisodium  phosphate.  This  is  usually  made  by  add- 
ing caustic  soda  to  the  ordinary  phosphate  of  soda 
and  is  mildly  alkaline  in  character.  By  its  use,  as  has 
been  noted,  in  the  case  of  sodium  aluminate,  the  waters 
are  both  softened  and  clarified.  The  lime  and  mag- 
nesia compounds  are  changed  into  phosphates  which 
are  insoluble,  thus  taken  out  of  solution,  and  are  floc- 
culent,  which  drag  down  any  substance  in  suspension 
as  clay,  mud,  or  precipitated  calcium  carbonate.  In 
this  condition  the  sludge  is  readily  blown  out. 

The  chemical  action  taking  place  is 

Calcium  sulphate  +  sodium  phosphate  =  sodium  sulphate  + 
3CaSO4          +          2Na3PO4         =        3Na2SO4         + 
calcium  phosphate 
Ca3P208 

Similar  reactions  take  place  with  the  bicarbonate  and 
magnesium  compounds. 

Composition  of  Some  Boiler  Scales.  —  Boiler  scales 


PITTING    AND    CORROSION 


119 


naturally  differ  according  to  the  waters  from  which 
they  are  formed;  from  fresh  water  they  may  or  may 
not  contain  a  quantity  of  calcium  sulphate;  from  sea- 
water  it  is  the  chief  incrusting  agent;  while  from  brack- 
ish waters  the  scale  contains  large  percentages  of  both. 
The  reason  for  the  absence  of  calcium  carbonate  in 
sea-water  scale  is  found  in  the  fact  that  the  marine 
animals  take  out  calcium  carbonate  for  the  material  of 
their  shells  —  oyster,  mussel  and  barnacle  shells, 
chalk  and  coral  being  mainly  composed  of  it.  Table 
III,  from  Lewes,  shows  the  analyses  of  boiler  incrus- 
tations from  their  different  sources. 

TABLE  III 


River  Water 

Brackish  Water 

Sea-Water 

Calcium  carbonate 

75-8 

43-6 

I.O 

Calcium  sulphate 

3-7 

34-8 

85.5 

Magnesium  hydrate 

2.6 

4-3 

3-4 

Salt 

0.4 

0.6 

2.8 

Sand 

7-7 

7-5 

i.i 

Oxides  iron  and  alumina 

3-° 

3-4 

o-3 

Organic  matter 

3-6 

1.6 

trace 

Moisture 

3-2 

4.2 

5-9 

Totals 

1  00.0 

IOO.O 

IOO.O 

Table  IV  shows  the  composition  of  some  boiler 
scales,  together  with  the  analyses  of  the  waters  from 
which  they  were  formed. 


I2O 


ENGINE-ROOM    CHEMISTRY 
TABLE  IV 


CHEMICAL  COMPOSITION  OF   SOME    BOILER   DEPOSITS    TOGETHER 
WITH  ANALYSIS  OF  THE  FEED-WATERS 


CONSTITUENTS 

No.  i 

No.  2 

No.  3 

No.  4 

Scale 

Water 

Scale 

Water 

Scale 

Water 

Scale 

Water 

Essential  Composition 

Calcium  carbonate(CaCOs) 

44-25 

8.30 

55-65 

14.78 

13.06 

Anhydrite  (CaSOO 

— 

49.98 

31.96 

Calcium  sulphate 

50.75 

29-73 

— 

74.07 

19.2 

(2CaSO4.H2O) 

Gypsum  (CaSO4.2H2O) 

— 

— 

— 

Magnesium  hydrate 

1.19 

3-83 

7.11 

Chemical  Composition 

Lime  (CaO) 

44-38 

45-o 

36.43 

4.60 

44-32 

iS-5 

38.80 

15-23 

Magnesia  (MgO) 

.82 

8-5 

2.64 

•9 

4.90 

6.8 

5-96 

3-7 

Ferric  oxide  and  alumina 

2.24 

1.67 

2.10 

.08 

O.I 

Silica  (SiO2) 

•47 

.88 

trace 

•65 

Water  given  off  above  120 

deg. 

3-68 

3-04 

2.31 

1.14 

Insoluble  matter 

.48 

5-65 

2.46 

Carbonic  acid  (CO2) 

19.25 

3-66 

24.48 

9-63 

Sulphuric  anhydride  (SOa) 

28.22 

21.9 

45-21 

4.0 

18.76 

8.9 

43-65 

12.3 

Lime 

22.5 

trace 

6.3 

Magnesia  deposited  on  boil- 

ing 

1.9 

o.o 

3-9 

Chlorine 

29-3 

— 

9.1 

Water  expressed  in  parts  per  100,000.      Scale  expressed  in  per  cent. 

The  following  experiments  will  illustrate  some  of  the 
points  brought  out  in  the  preceding,  regarding  hard 
water  and  scale-formation. 

Hard  water.  Prepare  artificial  hard  water  by  dis- 
solving calcium  carbonate  in  water  containing  carbonic 
acid  as  follows:  Lime-water  is  first  made,  then  car- 
bonic acid  is  passed  into  it;  slake,  with  a  small  amount 


PITTING    AND    CORROSION  121 

of  water,  a  piece  of  lime  as  big  as  a  marble,  putting  the 
white,  pasty  mass  into  a  quart  bottle,  nearly  filling  it 
with  water,  keeping  it  tightly  corked,  and  shaking  it 
from  time  to  time.  The  clear  liquid  is  lime-water.  To 
save  the  trouble  of  its  preparation  a  pint  may  be  ob- 
tained from  a  druggist. 

Make  a  generator  for  carbonic  acid  in  the  following 
manner:  Procure  a  wide-mouthed  bottle  of  about  a 
half-pint  capacity,  fitted  with  a  good  cork,  a  thistle  or 
funnel  tube,  a  piece  of  iVin.  glass  tubing  a  foot  long, 
and  a  piece  of  rubber  connecting  tubing  2  inches  long 
to  pass  over  the  glass  tubing.  By  heating  the  glass 
tubing  in  the  gas  or  alcohol-lamp,  rotating  it,  to  heat 
all  sides  equally,  soften  it,  and  make  a  right-angle  bend 
with  arm  2  inches  long  at  each  end  of  the  tube,  cut 
off  one,  making  an  elbow  with  2-in.  arms. 

The  tubing  is  cut  by  making  a  scratch  upon  it  with 
a  triangular  file,  then  holding  the  tubing  in  the  hands, 
with  the  thumb-nails  together  and  opposite  the  scratch, 
the  tube  is  partly  pulled  and  partly  bent  apart,  when 
it  will  break  squarely  at  the  scratch,  leaving  sharp 
edges.  These  should  be  removed  by  rotating  the  tub- 
ing against  the  file,  otherwise  they  will  cut  the  rubber 
connector  or  cork  like  a  keen  knife. 

.Now  with  a  round  file  make  two  holes  through  the 
cork  and  fit  the  thistle  tube  into  one  and  the  elbow  into 
the  other,  taking  care  that  they  make  a  snug  fit.  In 
fitting  these  tubes  they  should  be  wrapped  with  sev- 
eral thicknesses  of  towel  and  not  held  naked  in  the 
hand,  as  they  make  bad  cuts  in  case  of  breakage:  they 
may  be  wet  or  soaped  to  help  their  passage  into  the 


122  ENGINE-ROOM    CHEMISTRY 

cork.  By  means  of  the  rubber  connector  attach  the 
two  elbows  together  and  cut  off  the  longer  one,  or  de- 
livery tube  as  it  is  called,  so  that  when  the  generator 
sets  on  the  bench  the  delivery  tube  will  be  about  one- 
eighth  of  an  inch  from  it.  When  finished  the  genera- 
tor will  look  like  Fig.  34. 


FIG.  34.  — Carbonic  Acid  Generator 

Six  or  eight  bits  of  marble  or  limestone  as  large  as 
marbles  are  put  into  the  generator,  and  covered  with 
water,  a  half-teaspoonful  of  strong  muriatic  acid  being 
added  from  time  to  time;  a  brisk  bubbling  now  takes 
place,  and  a  gas,  carbonic  acid,  is  evolved  from  the 


PITTING    AND    CORROSION  123 

marble  and  conducted  into  half  of  the  lime-water  con- 
tained either  in  a  beaker  or  bottle.  A  white  precipitate 
of  calcium  carbonate  takes  place  which,  on  continued 
passing  of  the  gas,  dissolves.  It  is  not  necessary  to 
wait  until  it  all  dissolves,  but  after  the  gas  has 
passed  through  the  liquid  for  twenty  minutes  or  half 
an  hour,  it  may  be  discontinued,  the  liquid  allowed  to 
settle,  and  the  clear  solution  used  for  the  experiments. 
The  chemistry  of  what  has  taken  place  so  far  is  as  fol- 
lows: 

Calcium  carbonate  +  hydrochloric  acid  =  calcium  chloride  + 
(marble)  +    (muriatic  acid) 

CaCO3  +  2HC1  CaCl2  + 

carbonic  acid 
(H2C03)H20  +  C02 

Calcium  hydrate  4-  carbonic  acid  =  calcium  carbonate  +  water 
(lime-water)  (chalk) 

CaO2H2  +         CO2  CaCO3  +  H2O 

Calcium  carbonate  +  carbonic  acid  +  water  =  calcium  bicarbonate 
CaC03  +          C02          +  H20   =CaH2(C03)2  (soluble) 

(a)  To  slow  "temporary"  hardness.  Boil  half  a  test- 
tubeful  of  the  "clear  solution"  and  note  that  a  white 
precipitate  takes  place,  due  to  the  fact  that  the  car- 
bonic acid  is  driven  off  which  holds  the  calcium  car- 
bonate in  solution;  this  white  precipitate  is  calcium 
carbonate.  This  can  be  proved,  if  desired,  by  filtering 
off  the  precipitate,  dissolving  in  hydrochloric  acid  — 
note  the  bubbling  due  to  carbonic  acid  —  and  treating 
the  solution  with  ammonia  and  ammonium  oxalate, 
when  the  characteristic  white  precipitate  of  calcium 
oxalate  will  appear. 


124  ENGINE-ROOM    CHEMISTRY 

(b)  To  slow  the  softening  power  of  lime-water.     Add 
lime-water  to  some  of  the  "clear  solution"  in  a  test- 
tube   as   long    as    a    precipitate   is   produced.      The 
precipitate  is,  as  before,  calcium  carbonate,  and    is 
produced  for  two  reasons:  (i)  because  the  lime-water 
combines  with  the  carbonic  acid,  making  calcium  car- 
bonate; and  (2)  because  the  carbonic  acid  which  held 
some  calcium  carbonate  in  solution  being  removed, 
there  is  nothing  to  keep  it  in  solution.     Consequently 
it  is  precipitated.     Lime-water  is  extensively  used  as 
a  water-softening  agent;  caustic  soda  acts  in  an  ex- 
actly similar  manner.     Keep  some  of  the  "softened" 
water  to  try  its  action  with  soap. 

(c)  To  slow  the  softening  power  of  soda  ash.     Add  a 
pinch  of  soda  to  some  of  the  above-mentioned  "clear 
solution/'  and  note  the  familiar  precipitate  of  calcium 
carbonate,  due  to  the  reason  just  given  above.. 

To  show  the  softening  power  of  various  (<  boiler  com- 
pounds" (d)  tri-sodium  phosphate,  (e)  sodium  fluor- 
ide, (f)  sodium  aluminate  and  others,  obtain  small 
samples  from  the  dealers,  dissolve  in  water,  add  to  the 
"clear  solution"  and  note  the  kind  of  precipitate 
formed.  In  all  cases  up  to  the  present  the  precipitate 
has  been  calcium  carbonate  in  a  powdery  shape,  which 
is  not  as  efficient  for  removing  impurities  from  water  as 
a  flocculent  or  gelatinous  form.  In  the  case  of  the 
phosphate  and  aluminate,  this  kind  of.  precipitate 
will  be  obtained. 

(g)  To  show  the  effect  on  soap.  Treat  some  of  the 
"clear  solution"  in  a  test-tube  with  a  solution  of  soap 
and  note  the  curdy  precipitate,  lime  soap,  formed: 


PITTING    AND    CORROSION  125 

choose  two  test-tubes  of  practically  the  same  diameter 
and  put  into  one  two  inches  in  depth  of  the  "clear 
solution"  and  into  the  other  the  same  quantity  of  the 
"softened  water."  Add  to  each  of  these  soap  solu- 
tion from  a  medicine  dropper,  noting  the  number  of 
drops  in  each  case  until  a  permanent  lather  is  produced. 
The  "softened  water"  will  require  very  much  less  soap 
to  produce  the  same  lather. 

The  equations  below  indicate  what  has  taken  place 
in  the  various  experiments. 

TEMPORARY  HARDNESS 

Calcium  bicarbonate  =  calcium  carbonate  +  water  +  carbonic  acid 
CaH2(C03)2  CaC03  +   H2O  +  CO2 

SOFTENING  WITH  LIME-WATER 

Calcium  bicarbonate  +  lime-water  =  calcium  carbonate  +  water 
CaH2(CO3)2         +     CaO2H2    =  2CaCO3  +  2H2O 

SOFTENING  WITH  SODA  ASH 

Calcium  bicarbonate  +  soda  ash  =  calcium  carbonate  +  sodium  bi- 

(sodium  carbonate)  carbonate 

CaH2(CO3)2          +  Na,CO3  =  CaCO3  +  2NaHCO3 

SOFTENING  WITH  TRISODIUM  PHOSPHATE 

Calcium  bicarbonate  -f  trisodium  phosphate  =  calcium  phosphate  -f 
3CaH2(CO3)2        +  2Na3PO,  Ca3P2O8          + 

sodium  bicarbonate 
6NaHCO3 

SOFTENING  WITH  SODIUM  FLUORIDE 

Calcium  bicarbonate  +  sodium  fluoride  =  calcium  fluoride  + 
CaH2(CO3)2          +          2NaF  CaF2  + 

sodium  bicarbonate 
2NaHC03 


126  ENGINE-ROOM    CHEMISTRY 

SOFTENING  WITH  SODIUM  ALUMINATE 

Calcium  bicarbonate  +  sodium  aluminate  +  water  = 
CaH2(CO3)2          +          Na2Al2O4          +  aH2O  = 
sodium  carbonate  +  calcium  carbonate  +  aluminum  hydrate 
Na2CO3  +  CaCO3  +  2A1O3H3 

SOFTENING  WITH  SODIUM  STEARATE  (SOAP) 

Calcium  bicarbonate  +  sodium  stearate  =  calcium  stearate  + 
CaH2(C03)2          +          2NaSt  Ca(St)2          + 

sodium  bicarbonate 
2NaHCO3 

The  preceding  experiments  deal  with  hardness  due 
to  chalk  or  calcium  carbonate,  "limestone  hardness," 
as  distinguished  from  that  due  to  calcium  sulphate  or 
"gypsum  hardness."  A  hard  water  containing  cal- 
cium sulphate  can  be  made  by  gradually  adding  a  half- 
teaspoonful  of  plaster  of  Paris  to  two  tablespoonfuls  of 
water  contained  in  a  mortar  and  grinding  them  to- 
gether to  form  a  thin  paste.  It  is  occasionally  ground 
for  an  hour,  put  into  a  bottle  with  a  pint  of  water,  and 
allowed  to  stand  for  a  day  or  two  with  occasional  shak- 
ing. The  same  experiments  may  be  tried  with  this 
solution  as  with  the  foregoing  solution  of  bicarbonate 
of  calcium. 

Effect  of  boiling.  Note  that  on  boiling  little  or  none 
of  the  calcium  sulphate  is  precipitated.  If  it  were 
possible  for  you  to  heat  it  up  in  a  sealed  glass  tube 
to  280  degrees  Fahrenheit  it  would  be  practically  all 
precipitated. 

Effect  of  lime-water.  Note  that  lime-water  produces 
no  precipitate  in  the  calcium-sulphate  solution  as  it  did 
with  the  bicarbonate-of-lime  solution. 


PITTING    AND    CORROSION  127 

Effects  of  soda  ash,  sodium  phosphate,  fluoride,  almni- 
nate,  and  soap.  Note  that  these  are  practically  the 
same  as  with  water  containing  calcium  carbonate.  If 
a  solution  of  magnesium  bicarbonate  or  sulphate  were, 
used  the  results  would  not  be  essentially  different  from 
the  lime  salts  here  used. 


EXPERIMENTS  ILLUSTRATIVE  OF  CORROSION  AND  PIT- 
TING OF  IRON 

1 .  Effect  of  pure  water  on  iron  out  of  access  of  air.    Fill 
a  250-0:.  flask,  of  the  shape  shown  in  Fig.  4,  p.    19, 
two-thirds  fulls  of  freshly  distilled  water,  heat  it  to  boil- 
ing and  keep  it  gently  boiling  for  thirty  to  forty-five 
minutes,  tip  it  on   its  side  without  pouring  out  the 
water  and  slide  into  it  two  or  three  bright  steel  wire 
nails  which  have  been  carefully  wiped  free  of  any  oil  or 
dust;  cork  quickly  with  a  soft,  tight-fitting  cork  and 
allow  to  stand  a  few  days.     If  the  experiment  has  been 
properly  performed  the  nails  will  remain  bright. 

2.  Effect  of  pure  water  on  iron  with  access  of  air.     Re- 
peat experiment  No.  i  without  corking  the  flask.   Note 
the  rapidity  with  which  the  iron  is  rusted. 

3.  Effect  of  various  salts  contained  in  natural  waters 
on  iron.     Fill  a  number  of  6-in.  test-tubes  two-thirds 
full  of  the  following,  one  tube  of  each  being  sufficient : 
the  "clear  solution"  of  calcium  bicarbonate,  the  solu- 
tion of  gypsum  or  plaster  of  Paris,  these  representing 
hard  waters;  ordinary  well  water,  distilled  water  or 
rain  water,  or  soft  waters;    a  decoction  of  strong  boiled 
tea  or  infusion  of  peat  as  representing  peaty  waters, 


128  ENGINE-ROOM    CHEMISTRY 

distilled  water  with  about  one  gram  l  each  of  common 
salt,  niter,  and  sal  ammoniac,  representing  polluted 
waters;  and  of  quicklime,  soda  ash,  caustic  soda  or 
potash  (Babbitt's  lye)  (Be  careful),  trisodium  phos- 
phate, sodium  aluminate,  fluoride,  or  any  boiler 
compound  as  representing  water  softeners  or  boiler  com- 
pounds. Incline  the  tubes  as  much  as  possible  with- 
out spilling  the  water,  and  slide  into  them  two  bright 
clean  steel  wire  nails  as  above.  Observe  and  note  the 
action  on  the  nails,  half  an  hour,  one  hour,  three  hours, 
and  five  hours  after  inserting  the  nails;  let  the  tubes 
stand  for  a  few  days,  and  note  the  results,  recording 
them  morning  and  evening.  The  results  of  experi- 
ments made  in  the  author's  laboratory  are  shown  in 
Table  V. 

Effect  of  metals,  coke,  scale,  etc.,  on  the  corrosion  of 
iron.  Bind  lightly  together  by  means  of  a  piece  of 
florists'  wire,  two  bright,  clean,  steel  wire  nails,  and 
with  one  end  of  the  wire  still  attached  to  them,  wind 
the  other  end  around  a  small  piece  of  electric-light  or 
dynamo-brush  carbon,  leaving  perhaps  four  inches  of 
wire  between  them.  Put  the  nails  and  carbon  into  a 
250-0:.  beaker  or  half-pint  wide-mouthed  bottle  or 
tumbler  of  clear  glass,  keeping  them  separate,  and 
cover  them  about  two  inches  deep  with  tap  water, 
leaving  the  wire  exposed. 

Repeat  this  experiment,  using  instead  of  carbon  a 
lump  of  soft  or  hard  coal,  some  iron  hammer  or  forge 
scale,  a  piece  of  copper,  another  of  brass,  a  bit  of 
zinc  or  aluminum,  and  two  other  nails. 

1  One  gram  represents  a  lump  twice  the  size  of  a  pea. 


PITTING    AND    CORROSION 


129 


TABLE   V 

RESULTS  OF    EXPERIMENTS    MADE    TO    SHOW    THE    RUSTING    OF 

STEEL  NAILS  IN  ARTIFICIAL  HARD  AND  POLLUTED  WATERS, 

AND  IN  BOILER  COMPOUNDS 


DESCRIPTION 
OF  WATER 

CONDITION  AT  TIMES  SPECIFIED 

fhr. 

i|  hrs. 

3  hrs. 

3  days 

6  days 

Lime 

Bright 

Bright 

Bright 

Bright 

Bright 

Gypsum 

Slight  rust 

More  rust 

Very  slight  rust 

Some  rust 

Considerable 

Bicarbonate 

Bright 

Bright 

Very  slight  rust 

Slight  rust 

rust 

of  lime 

Some  rust 

Tap  (Boston) 

Slight  rust 

More  rust 

More  rust 

Less  than 

About  \  that 

No.  2 

on  No.  2 

Distilled 

Slight  rust 

More  rust 

Rust  spots 

Less  than 

About  §  that 

No.  2 

on  No.  2 

Peaty 

Bright 

Bright 

Bright 

Very  slight 

Very  slight 

Salt 

Bright 

Very  slight  rust 

Very  slight  rusl 

Rust 

About  |  No.  2 

Niter 

V  slight  rust 

Slight  rust 

Bad  spots 

About 

About  ij 

twice  No.  2 

No.  2 

Sal  ammoniac 

Slight  rust 

More  rust 

Very  slight 

as  No.  2 

as  No.  2 

Carb.  soda 

Bright 

Bright 

Bright 

Bright 

Bright 

Caustic  soda 

Bright 

Bright 

Slight  pits. 

Bright 

Bright 

Aluminate 

soda 

Bright 

Bright 

Slight  pits. 

Bright 

Bright 

Phosphate 

soda  (tri.) 

Bright 

Bright 

Slight  pits. 

Bright 

Bright 

As  illustrating  pitting,  prepare  a  half-dozen  pieces  of 
bright  iron  or  steel  as  large  as  a  quarter,  but  square: 
in  the  center  of  each  of  these  place  a  bit  of  hammer  or 
forge  scale,  a  piece  each  of  coal.,  electric-light  carbon, 
and  copper,  a  bit  of  zinc  and  a  small  piece  of  the  same 
iron.  Put  them  all  in  an  enameled  iron  hand-basin, 
into  which  a  stream  of  tap  water  as  large  as  a  knitting 


130  ENGINE-ROOM    CHEMISTRY 

needle  is  constantly  flowing,  and  let  them  stand  for  two 
or  three  weeks. 

The  experiment  with  nails  coupled  with  carbon, 
zinc,  coal,  etc.,  as  carried  on  for  six  days  in  the  writer's 
laboratory,  showed: 

With  zinc  very  little  action. 

With  nails  some  action. 

With  coal  about  twice  the  action  with  zinc. 

With  carbon  about  four  times  the   action   with 

zinc. 
With  copper  about  thrice  the  action  with  zinc. 

This  shows  the  protective  effect  of  the  zinc  and  the 
opposite  action  of  the  coal,  copper,  and  arc-light  carbon. 
Practically  the  same  results  were  obtained  in  two 
weeks  with  the  iron  squares:  all  were  more  or  less 
rusted  by  the  exposure;  but  the  pitting  was  very 
marked  with  the  arc-light  carbon,  the  coal,  the  copper, 
and  the  hammer  scale. 

TESTS  TO  BE  APPLIED  TO  FEED-WATERS 

Boiling  Test.  Boil  a  test-tube  two-fifths  full  of  the 
water:  if  a  white  powder  or  precipitate  appears,  it  in- 
dicates bicarbonate  of  lime  or  magnesia. 

Soda  Ash  Test.  If,  after  the  above  boiling,  the  water 
remains  clear,  add  a  quantity  of  sodium  carbonate 
(soda  crystals  or  soda  ash)  as  large  as  half  a  pea,  and 
continue  boiling:  a  white  precipitate  indicates  the 
presence  of  gypsum  or  sulphate  of  lime,  or  possibly 
magnesium  sulphate  (Epsom  salts). 

Alcohol  Test.    Add  to  one-fifth  of  a  test-tubeful  of 


PITTING    AND    CORROSION  131 

water  double  its  volume  of  the  strongest  alcohol  ob- 
tainable, 90  per  cent,  or  over:  a  white  precipitate  shows 
the  presence  of  sulphate  of  lime;  if  slightly  milky, 
about  250  parts  per  million  are  present;  if  a  "good" 
test,  about  twice  this  amount. 

Silver  Nitrate  Test.  Add  to  one-half  a  test-tubeful  a 
few  drops  of  silver  nitrate:  a  precipitate  indicates  chlo- 
rides and  carbonates.  Add  a  few  drops  of  chemically 
pure  nitric  acid,  when,  if  the  cloudiness  or  precipitate 
be  due  to  carbonates,  it  will  clear,  leaving  that  due  to 
chlorides.  Chlorides,  as  already  explained,  are  corro- 
sive agents,  and  come  from  rock-salt  deposits  and  sea- 
water. 

With  the  exception  of  the  boiling  test,  it  may  be  nec- 
essary to  boil  down  or  evaporate  the  water  in  a  porce- 
lain dish  to  one-half  or  three-fourths  of  its  original 
volume. 

If  the  total  amount  of  lime  and  magnesia  compounds 
calculated  as  carbonate,  sulphate,  and  chloride,  as 
shown  by  a  chemical  anlysis  of  the  water,  be  between 
137  and  258  parts  per  million,  the  water  may  be  classed 
as  "good";  if  from  258  to  344  parts,  the  water  is  only 
"fair." 

The  analysis  of  scale  has  already  been  given  on  p.  38. 


VI 

MINERAL  OILS 

THE  mineral  oils  are,  chemically  speaking,  hydro- 
carbons, i.e.,  bodies  composed  of  carbon  and  hydrogen, 
and  as  such  are  the  least  liable  to  change  or  "gum"  of 
any  of  the  oils.  They  are  obtained  by  distilling  crude 
petroleum  or  rock  oil,  usually  a  dark-colored  strong- 
smelling  liquid. 

Several  theories  have  been  proposed  as  to  the  origin 
of  petroleum:  one  is  that  it  was  formed  from  the  flower- 
less  plants  and  simple  animals  at  about  the  same  time 
and  in  a  similar  manner  as  was  coal;  another  that  it 
was  produced  by  the  natural  distillation  of  the  fat  of 
the  fish  that  were  so  abundant  just  subsequent  to  the 
coal  period.  Professor  Engler  has  substantiated  this 
theory  by  distilling  half  a  ton  of  menhaden  oil  at  a 
pressure  of  150  pounds  and  obtaining  a  product  re- 
sembling crude  petroleum,  from  which,  by  distillation, 
a  good  illuminating  oil  was  prepared. 

Petroleum  is  found  in  many  localities,  of  which  those 
in  Pennsylvania,  Ohio,  Ontario,  and  Russia  are  the 
most  important.  It  is  obtained  by  drilling  a  well  like 
an  Artesian  well,  until  the  oil-sands  are  reached,  usu- 
ally at  a  depth  of  1800  or  2000  feet,  whence  the  oil 
gushes  for  a  time  and  afterward  requires  to  be  pumped. 

132 


MINERAL    OILS 


Such  a  well  costs  about  $3500  and  may  yield  a  few  or 
several  hundred  barrels  per  day. 


FIG.  35.  —  Cheese-box  Still.      Cross  Section 

Lubricating  oils  are  prepared  by  distilling  off  from 
the  crude  petroleum  the  lighter  or  more  volatile  por- 
tions, as  the  naphthas,  kerosenes,  etc.,  leaving  the 


Diameter  of  Brick  Work  at  Base  Line  S3  «' 

FIG.  36.  — Plan  of  Cheese-box  Still 

heavier  portions.     These  latter  in  some  cases  require 
no  further  treatment,  forming  the  "reduced  oils";  or 


134  ENGINE-ROOM    CHEMISTRY 

they  are  distilled,  treated  with  sulphuric  acid,  and 
washed  with  soda  and  water,  forming  the  "  distilled  oils." 
The  process  of  distillation  1  is  effected  in  huge  up- 
right or  "cheese-box"  stills  (Figs.  35  and  36)  30  ft.  in 


FIG.  37.  —  Horizontal  Still 

diameter  and  10  ft.  in  hight,  of  boiler  iron,  holding 
about  a  thousand  barrels:  horizontal  stills  (Figs.  37  and 


38)  30  ft.  in  length  and  10  ft.  in  diameter,  containing  600 
barrels,  are  often  employed.    These  are  heated  by  coal 

1  The  process  of  distillation  consists  in  changing  the  substance  distilled  to  vapor, 
and  chilling  or  condensing  this  vapor:  an  ordinary  steam  boiler  is  a  still;  "returns" 
serve  as  a  condenser;  and  the  "drip,"  or  condensed  water,  as  "distilled  water." 
Distillation  is  a  common  method  of  separating,  or  purifying,  liquids  of  different  boil- 
ing-points, as  alcohol  and  water,  or  the  mixture  contained  in  crude  petroleum. 


MINERAL    OILS  135 

fires  and  supplied  with  superheated  steam  to  aid  in 
carrying  the  heavy  oil  vapors  rapidly  out  from  the 
still.  These  vapors  pass  into  iron  coils  or  condensers 
(Fig.  39)  where  they  are  condensed  to  a  liquid:  accord- 
ing to  the  specific  gravities  of  these  liquids  or  distillates 
they  are  classed  as  gasolenes,  naphthas,  kerosenes,  etc. 
The  residue  remaining  in  the -large  still  is  transferred 


FIG.  39.  —  Condenser 

to  cylindrical  cast-iron  stills  and  distilled  from  soda 
solution,  yielding  finally  kerosenes,  "mineral  sperm," 
and  the  various  grades  of  engine  oils,  cylinder  oils,  vas- 
eline, and  heavy  greases. 

The  refining  process  consists  in  removing  the  odor 
and  the  tarry  matters  formed  in  the  process  of  distilla- 
tion, and  in  improving  the  color:  it  is  effected  by  agi- 


i36 


ENGINE-ROOM    CHEMISTRY 


tating  the  oil  in  tall  tanks  with  sulphuric  acid,  using 
compressed  air,  or  in  the  case  of  the  lighter  distillates, 
mechanical  stirrers.  The  oil  is  allowed  to  stand  to 
separate  the  tar  and  sulphuric  acid,  the  latter  is  drawn 
off,  and  the  oil  washed  with  soda  solution  and  finally 
with  water.  The  color  of  oils  is  removed  by  the  acid 
treatment  followed  by  sunning,  and  in  the  case  of  the 
lubricating  oils  by  filtration  through  bone  charcoal 
after  the  manner  of  sugar  syrups. 

Table  VI  shows  some  of  the  principal  products  de- 
rived from  petroleum,  together  with  their  properties 
and  uses. 

TABLE  VI 


Name 

Gravity, 
Degrees  B. 

Boiling-point, 
Degrees  F. 

Use 

Cymogene  

N 

no-ioo 
loo-  go 
90-  80 
80-  75 
76-  70 
67-  62 
62-  57 

BURN 

57-  53 
53-  5° 
5°-  47 
39-  36 

APHTHAS 

32 

65 

100-150 
150-190 
160-210 
160-225 

225-300 

ING    OILS 

Fire  test 
no 

120 

iSS-^0 
300 

Ice  machines 
Anesthesia 
Gas  machines 
Oil  extraction 
Automobiles 
Stoves 
For  turpentine 

Burning  (China) 
"        (England) 
"        (America) 
"        (cars   and 
boats,  lanterns) 

Rhigolene         

Petroleum  ether  .  .  . 
Gasolene 

Naphtha  
Ligroine                .  .  . 

Benzine  
Export  oil  

Export  oil 

Kerosene  

Mineral  sperm  .... 

MINERAL    OILS 
LUBRICATING  OILS 


Name 

Gravity 

Flash 

Cold  Test 

Viscosity 

Spindle  oils: 
No.  4  Eagle  
No.  i  Eagle      .  . 

Deg.  B. 

344 
30.3 

Deg.  F. 
320 
3QO 

Deg.  F. 

25 

2< 

Seconds 
72  at  7o°F. 
200 

Engine  oil    

Engine  oil    . 

3*-7 
27.9 

•300 
3^0 

30 

32 

49 
104 

Engine  oil    
Bayonne  engine  oil  .  . 
Cylinder  oil    

24.9 
23.1 
28.1 

395 

4i5 
soo 

32 

34 

cjo—  c;c 

220 
400 

117  at  2i2°F. 

Cylinder  oil    
Cylinder  oil    

27-5 
26.1 

55° 
600 

5° 
2C 

15° 

2OO 

Testing  of  Mineral  Lubricating  Oils.  -  -  The  tests 
which  it  is  feasible  to  perform  outside  a  well-equipped 
laboratory  are:  viscosity,  specific  gravity,  cold  test, 
flash  test,  fire  test,  gumming  test,  acidity,  for  animal 
and  vegetable  oils,  and  for  "oil-pulp." 

Viscosity  Test.  By  viscosity  we  understand  the 
degree  of  fluidity  of  an  oil  or  its  internal  friction; 
or  its  "body"  or  "greasiness"  as  it  is  sometimes  ex- 
pressed. Other  things  being  equal,  the  least  viscous 
oil  should  be  chosen,  or,  otherwise  expressed,  the  most 
fluid  oil  that  will  stay  in  place  and  do  the  work.  A 
case  is  on  record  in  which  the  changing  of  a  spindle  oil 
to  one  slightly  more  viscous  caused  the  stopping  of  an 
engine  and  hence  the  whole  mill,  due  to  the  increase 
in  friction.  Within  certain  limits,  it  may  be  taken  as 
the  measure  of  the  value  of  an  oil  as  a  lubricant,  par- 
ticularly if  the  viscosity  of  the  oil  under  examination 


138  ENGINE-ROOM    CHEMISTRY 

be  compared  with  that  of  other  oils  which  have  been 
found  to  yield  good  results  in  practice. 

The  instruments  employed  for  the  determination  qf 
viscosity  are  constructed  upon  two  different  principles : 
one  depending  upon  the  time  required  for  a  certain 
quantity  of  the  oil  to  flow  through  a  standard  orifice, 
as  the  Saybolt,  Tagliabue,  Redwood,  and  Engler;  and 
the  other,  upon  the  degree  to  which  a  disk  is  hindered 
in  rotating,  by  the  viscosity  of  the  oil,  as  the  Doolittle. 

The  Saybolt  apparatus,  which  may  be  taken  as  a  type 
of  the  orifice  instruments,  will  be  described  here.  It 
is  made  in  three  forms,  A,  B,  and  C.  Apparatus  "A" 
is  the  standard  for  testing  at  70  deg.  F.  Atlantic  Red, 
Paraffin,  and  other  distilled  oils;  "B"  for  testing  at 
70  deg.  F.  black  oils  of  o,  15,  25,  and  30  degrees  Cold 
Test,  and  other  reduced  oils  up  to,  and  not  including, 
Summer  Cold  Test  oil;  and  "C"  is  used  for  testing  at 
212  deg.  F.  Reduced,  Summer,  Cylinder,  Filtered  Cylin- 
der, XXX  Valve,  26.5  deg.  B.,  and  other  heavy  oils. 
The  results  are  reported  in  seconds. 

Apparatus  "A,"  -Description.  —  The  "A"  appa- 
ratus (Fig.  40) l  consists  of  a  brass  tube  T,  containing 
about  66  cubic  centimeters,  and  about  three  centi- 
meters in  diameter  and  eight  centimeters  long,  forming 
the  body  of  the  pipette.  It  is  connected  at  the  bottom 
with  a  smaller  tube  /,  having  a  window  w.  This  pi- 
pette is  screwed  into  the  piece  p  carrying  the  jet,  1.75 
millimeters  in  diameter;  the  lower  part  of  this  piece  is 
expanded  at  the  bottom  to  admit  of  the  insertion  of  a 

1  This,  as  well  as  some  other  tests,  is  taken  from  the  writer's  "  Short  Handbook 
of  Oil  Analysis." 


MINERAL    OILS  139 

cork.  The  upper  part  of  the  pipette  is  perforated  with 
a  number  of  small  holes  leading  to  a  gallery  G,  5  cm. 
in  diameter  and  i  .3  cm.  deep.  This  enables  a  workman 
to  fill  the  apparatus  to  the  same  point  every  time.  The 
pipette  is  held  by  p  in  a  tank  of  water  18  cm.  high  and 
20  cm.  in  diameter,  also  provided  with  windows  to 
observe  the  efflux  of  the  oil..  A  tin  cup  with  spout, 


FIG.  40.  —  Saybolt  Viscosimeter 

thermometer,  pipette  with  rubber  bulb,  stop-watch, 
and  beaker  for  waste  oil,  complete  the  outfit. 

Having  the  bath  of  water  prepared  at  70  deg.  and 
the  oil  in  the  tin  cup  about  69.5  deg.,  clean  the  tube 
out  with  some  of  the  oil  to  be  tested  by  using  the  plun- 
ger P  sent  with  the  instrument.  Place  the  cork  air- 
tight in  the  lower  outlet  tube  and  pour  the  oil 


140  ENGINE-ROOM    CHEMISTRY 

into  the  tube  proper  until  it  flows  into  the  overflow 
cup. 

By  stirring  with  the  thermometer,  bring  the  oil  to  ex- 
actly 70  deg.,  remove  the  thermometer,  and  draw  with 
a  pipette  the  surplus  oil  in  the  overflow  cup  down  below 
the  overflow  holes.  The  temperature  still  remaining 
constant,  with  the  watch  in  the  left  hand,  draw  the 
cork  with  the  right,  and  simultaneously  start  the  watch.  • 
Toward  the  end  of  the  run,  watch  the  peep-hole  closely 
through  the  window  in  the  bath,  and  at  the  first 
appearance  of  space  not  filled  with  oil  in  the  glass 
outlet,  stop  the  watch.  The  number  of  seconds  that 
have  passed  between  the  starting  and  stopping  of 
the  watch  is  the  viscosity  of  the  oil. 

Specific  Gravity.  By  specific  gravity  we  understand 
the  weight  of  a  substance  compared  with  the  weight 
of  an  equal  volume  of  water.  The  specific  gravity  of 
iron  is  7.8:  this  means  that  a  cubic  inch  of  iron  weighs 
7.8  times  as  much  as  a  cubic  inch  of  water.  In  accu- 
rate work,  attention  has  to  be  paid  to  the  temperature. 
In  the  case  of  oils,  the  specific  gravity  is  expressed  in 
terms  of  the  Baume  (pronounced  "Bomay")  scale 
for  liquids  lighter  than  water.  This  is  an  arbitrary 
scale  in  which  water  counts  as  10  degrees.  For  ex- 
ample, a  76-deg.  naphtha,  a  25-deg.  lubricating  oil, 
means  that  the  Baume  hydrometer  would  sink  in  the 
naphtha  to  the  seventy-fifth  degree  and  in  the  lubri- 
cating oil  to  the  twenty-fifth  degree,  both  these  liquids 
being  cooled  to  60  deg.  F.  The  mineral  oils  are  usually 
designated  by  the  Baume  scale,  while  the  animal  and 
vegetable  oils  are  spoken  of  in  terms  of  specific  gravity: 


MINERAL    OILS  141 

cottonseed  oil  has  a  gravity  of  0.922,  meaning  that  a 
quart  of  cottonseed  oil  is  nine  hundred  and  twenty-two 
thousandths  as  heavy  as  a  quart  of  water.  The  chief 
value  of  the  test  is  to  characterize  the  oil.  This  is 
usually  effected  by  the  hydrometer.  A  hydrometer  jar 


FIG. 41. — 
Baume  hydrometer 

is  four-fifths  filled  with  the  oil,  a  Baume  hydrometer 
(Fig.  41)  introduced  into  it,  and  the  depth  to  which 
the  instrument  sinks  in  the  oil  (Fig.  42)  read  off. 
This  may  be  effected  by  placing  a  strip  of  white  paper 
back  of  the  jar  and  noting  the  point  at  which  the  lower 


142 


ENGINE-ROOM    CHEMISTRY 


meniscus  or  curve  of  the  surface  of  the  oil  touches  the 
scale,  as  at  20  deg.  as  shown  in  the  figure.  The  tem- 
perature of  the  oil  is  taken  at  the  same  time,  and  in 
case  it  be  not  60  deg.  F.  (15.5  deg.  C),  for  every  in- 
crease of  10  deg.  F.  (5.5  deg.  C.),  subtract  i  deg.  B. 
from  the  hydrometer  reading.  The  specific  gravity 


may  be  found  by  the  formula 


144-3 


-,  B°represent- 


FIG.  42.  — Stem  of 
Baume  Hydro- 
meter 

ing  the  reading  Baume.  In  practice  this  reduction 
can  be  done  by  Tagliabue's  ''Manual  for  Inspectors 
of  Coal  Oil." 

It  is  possible  that  the  Saybolt  viscosimeter  cannot 
be  obtained,  in  which  case  recourse  must  be  had  to 
Engler's  or  other  viscosimeters.  Instructions  for 
using  the  apparatus  accompany  it. 

Cold  Test.    This  may  be  defined  as  the  temperature 


QF  THE 

((  UNIVERSITY 


MINERAL    OILS  143 

at  which  the  oil  will  just  flow.  The  importance  of  this 
test  is  seen  wherever  oils  are  exposed  to  freezing  tem- 
peratures, as  for  example  in  railroad  use  on  car  axles: 
if  the  oil  be  chilled  it  ceases  to  flow  and  the  bearing 
becomes  hot;  or,  as  has  happened  on  the  East  -Prus- 
sian railroad,  the  freezing  of  the  oil  in  the  axle-boxes 
stops  the  running  of  the  trains. 

The  apparatus  required  comprises:  a  four-ounce 
vial;  a  thermometer;  a  quart  can;  and  a  freezing 
mixture. 

The  four-ounce  vial  is  one-fourth  filled  with  the  oil 
to  be  examined,  a  short,  rather  heavy,  thermometer 
inserted  in  it,  and  the  whole  placed  in  a  freezing  mix- 
ture. When  the  oil  has  become  solid  throughout,  the 
vial  is  removed,  the  oil  allowed  to  soften,  and  thor- 
oughly stirred  until  it  will  run  from  one  end  of  the 
bottle  to  the  other.  The  reading  of  the  thermometer 
is  now  taken  by  withdrawing  it  and  wiping  off  the  oil 
with  waste  to  render  the  mercury  visible. 

The  chilling-point  is  the  temperature  at  which  flakes 
or  scales  begin  to  form  in  the  liquid,  and  is  determined 
similarly,  by  cooling  the  liquid  five  degrees  at  a 
time. 

As  freezing  mixtures,  for  temperatures  above  35  deg. 
F.  use  cracked  ice  and  water;  between  35  and  o  deg.  F. 
use  two  parts  of  ice  and  one  part  of  salt;  and  from 
o  to  30  deg.  F.  use  three  parts  of  crystallized  calcium 
chloride  and  two  parts  of  fine  ice  or  snow.  A  still 
more  convenient  means  is  by  the  use  of  solid  car- 
bonic acid,  "carbonic  acid  snow,"  dissolved  in  ether 
or  alcohol,  giving  -50  deg.  F.  readily. 


144 


ENGINE-ROOM    CHEMISTRY 


Flash-Point.  By  flash-point  is  understood  that 
temperature  at  which  an  oil  gives  off  vapors  in  suffi- 
cient quantity  to  explode  when  mixed  with  air:  this 
point  is  reached  by  burning  oils  in  testing  when  a  blue 
flame  passes  entirely  over  the  surface  of  the  oil;  in 


G- 


FIG.  43. —  Flash-point  apparatus  for 
Lubricating  Oils 

lubricatjng  oil,  when  a  puff  of  flame  comes  out  of  the 
testing-hole  in  the  cover.  Like  specific  gravity,  the 
chief  use  of  the  test  with  lubricating  oils  is  to  ascertain 
if  any  change  has  been  made  in  the  oil  supplied.  With 
burning  oils  it  determines  the  safety  of  the  oil.  In 


MINERAL    OILS  145 

considering  the  results  of  this  test,  differences  of  five 
to  seven  degrees  F.  may  be  disregarded,  as  duplicate 
tests  upon  the  same  sample  may  vary  as  widely  as 
this. 

Several  forms  of  apparatus  for  testing  the  flash-point 
of  lubricating  oils  have  been  devised:  Pensky-Martens' 
closed  tester  employing  a  stirrer  is  used  in  Germany. ' 
Martens  states  in  a  later  article  that  stirring  is  unnec- 
essary. Dudley  and  Pease  use  an  open  porcelain  dish 
heated  with  a  Bunsen  burner.  The  apparatus  in  use 
in  the  author's  laboratory  is  similar  to  the  New  York 
State  tester,  and  consists  of  a  covered  copper  cup  - 
shown  at  about  one-tenth  the  size  in  Fig.  43  and  drawn 
to  scale  in  Fig.  47  (see  Appendix,  page  188),  supported 
by  gauze  upon  an  iron  stand  and  heated  by  a  Tirrill 
burner. 

The  cup  is  filled  with  oil  to  within  f-inch  of  the  flange 
(in  case  of  cylinder  or  oils  flashing  above  500  degrees, 
i-inch),  all  air-bubbles  removed  by  pricking  with  a 
pointed  stick,  the  flange  and  top  of  cup  carefully  wiped 
free  of  oil,  the  cover  put  on,  and  the  thermometer  in- 
serted so  that  its  bulb  is  half-way  between  the  surface 
of  the  oil  and  the  bottom  of  the  cup.  The  lamp,  carry- 
ing a  flame  about  an  inch  in  hight,  is  placed  under- 
neath, the  bottom  of  the  cup  being  two  and  one-half 
inches  from  the  mouth  of  the  burner,  and  the  heating 
commenced.  The  rate  of  heating  should  be  1 5  deg.  F. 
per  minute,  and  may  be  easily  regulated  by  the  burner 
used.  The  testing  flame  should  be  first  applied  at 
250  deg.  F.,  and  then  every  half-minute  until  the  flash- 
point is  reached.  This  is  indicated  by  a  slight  puff  of 


146  ENGINE-ROOM    CHEMISTRY 

flame  out  of  the  testing-hole.  The  results  obtained 
with  this  apparatus  agree  better  among  themselves 
than  those  obtained  with  the  open  tester;  they  are 
usually  15  to  25  degrees  lower. 

Fire  Test.  The  fire  test  is  that  temperature  at 
which  an  oil  gives  off  vapors  in  sufficient  quantity  to 
burn  continuously  when  a  flame  is  applied.  The  cover 
is  supported  above  the  cup,  and  the  heating  and  appli- 
cation of  the  testing  flame  continued  as  in  making  the 
flash  test. 

The  method  of  recording  is  the  same  as  in  the  case  of 
the  illuminating  oils,  one  column  for  times  and  another 
for  temperatures.  Holde  finds  that  with  oils  flashing 
between  340  and  465  degrees  F.  the  exact  quantity  of 
oil  used  is  of  little  importance.  In  these  particular 
cases  a  difference  of  filling  of  thirteen  cubic  centimeters 
altered  the  flash-point  only  two  or  three  degrees  F. 

It  is  worthy  of  notice  that  the  free  acid  (oleic  acid) 
contained  in  an  oil  lowers  its  flash-point  apparently  in 
proportion  to  the  quantity  present. 

Gumming  Test.  This  is  designed  to  give  an  idea  of 
the  amount  of  change  that  may  be  expected  in  a  min- 
eral oil  when  in  use.  These  resinified  products  increase 
the  friction  of  the  revolving  or  rubbing  surfaces.  The 
test  is  applied  by  thoroughly  mixing  and  beating  to- 
gether 5  grams  of  the  oil  in  a  cordial  glass  or  small 
wide-mouthed  bottle  with  1 1  grams  of  nitrosulphuric 
acid,  and  cooling  by  setting  the  glass  in  a  basin  of  water 
at  50  to  60  degrees  F.  Brownish  spots  or,  in  case  of  a 
bad  oil,  masses  form  around  the  edges  and  gradually 
cover  the  whole  surface  in  the  course  of  two  hours.  As 


MINERAL    OILS  147 

shown  by  long  practical  experience,  the  oil  showing 
the  least  tar  is  the  best  oil  and  also  absorbs  the  least 
oxygen. 

Nitrosulphuric  acid  is  troublesome  to  prepare;  but 
directions  therefor  will  be  found  in  the  writer's  "  Hand- 
book of  Oil  Analysis,"  and  it  may  be  replaced  by  nitric 
acid  and  copper.  Use  ordinary  nitric  acid,  1.34  sp. 
gr.,  drop  into  this  two  pieces  of  No.  15  B.  &  S.  gage 
copper  wire  f-inch  long,  and  in  an  hour  two  more 
pieces. 

Test  for  Acidity.  In  a  petroleum  oil  the  acid  pres- 
ent is  usually  sulphuric,  owing  to  the  acid  used  in 
refining  being  incompletely  washed  out  of  the  oil.  Its 
presence  can  be  detected  by  shaking  about  one-fourth 
of  a  test-tubeful  of  oil  with  an  equal  quantity  of 
warm  distilled  water  in  a  test-tube.  The  oil  is  poured 
off  carefully,  and  the  water  tested  with  neutral  litmus 
paper,  which  in  presence  of  acid  is  changed  to  red.  If 
the  litmus  paper  used  were  too  blue,  the  acid  might  be 
all  used  up  before  the  color  changed ;  hence  in  this  case 
it  should  be  exposed  to  the  fumes  of  hydrochloric  acid 
until  nearly  neutral.  A  test  should  be  made  to  be  sure 
that  the  water  is  not  acid.  Not  more  than  a  faint  red- 
dening is  allowable:  the  acid  content  should  not  ex- 
ceed 0.3  per  cent.,  calculated  as  sulphuric  anhydride 
(SO,). 

Test  for  animal  and  vegetable  oils  in  mineral  oils.  Put 
about  an  inch  of  the  oil  into  each  of  two  test-tubes; 
add  to  one  of  these,  two  pieces  of  metallic  sodium  as 
large  as  half  a  pea  and  to  the  other  a  similar  quantity 
of  sodium  hydrate  (caustic  soda).  Extreme  care 


148  ENGINE-ROOM    CHEMISTRY 

should  be  taken  in  handling  these  substances  as  the 
metallic  sodium  takes  fire  if  wet.  forming  caustic  soda 
which  attacks  the  skin  and  clothing  vigorously:  if 
any  gets  upon  either,  wash  it  off  with  water  and  dilute 
muriatic  acid,  and  the  acid  with  water.  Heat  the  test- 
tubes  in  an  oil  bath,  that  is,  an  iron  pot  containing 
heavy  cylinder  oil,  lard,  or  cottonseed  oil,  deep  enough 
to  cover  the  oil  surface  in  the  tube  to  a  temperature 
of  about  445  deg.  F.,  in  case  the  oil  be  a  light-colored 
one,  and  to  480  deg.  F.  if  it  be  dark-colored.  In  case 
fatty  oil  be  present,  the  contents  of  one  or  both  of  the 
tubes  show  a  foam  as  of  soap  bubbles  on  the  surface, 
and  solidify  to  a  jelly  of  greater  or  less  consistency  ac- 
cording to  the  amount  of  fatty  oil  present. 

Detection  of  "oil-thickener"  or  "oil-pulp."  This  is 
usually  an  oleate  of  aluminum,  a  soap,  which  is  dis- 
solved in  the  oil  to  increase  its  viscosity  at  ordinary 
temperatures,  but  has  little  effect  on  the  oil  at  the 
temperature  at  which  it  is  used.  It  may  be  detected 
by  diluting  the  oil  with  an  equal  quantity  of  naphtha 
and  adding  about  15  drops  of  a  saturated  solution  of 
stick  phosphoric  acid  in  absolute  (100  per  cent.) 
alcohol.  The  mixture  is  allowed  to  stand,  when  the 
formation  of  a  flocculent  precipitate  indicates  the  pres- 
ence of  soap. 

As  showing  the  extent  to  which  it  affects  the  viscos- 
ity, a  sample  of  oil  containing  it  would  .not  flow  from 
the  viscosimeter  at  70  deg.  F.,  required  1 167  seconds  at 
85  degrees  and  181  seconds  at  no  degrees. 

A  test  which  is  often  applied  to  light  oils,  like  spindle 
and  loom  oils,  is  the  evaporation  test:  this  measures 


MINERAL    OILS  149 

the  loss  sustained  by  an  oil  when  exposed  on  a  bearing. 
It  requires  a  delicate  analytical  balance,  sensitive  to 
TV  milligram  (0.0015  grain),  to  detect  the  loss,  as  the 
amount  of  oil  used  is  small  (200  milligrams).  The 
amount  of  loss  should  not  exceed  4  per  cent.  The  test 
is  important  to  the  mill-owner  as  it  represents  the 
amount  of  oil  that  stays  on  the  bearing  and  serves  its 
purpose.  It  is  of  even  greater  importance  to  the  in- 
surance underwriter,  as  it  measures  the  amount  of 
volatile  inflammable  matter  passing  into  the  atmos- 
phere and  liable  to  cause  a  fire.  This  actually  hap- 
pened in  a  spinning-mill  in  Maine:  the  oil  contained, 
however,  25  per  cent,  of  volatile  matter;  that  is,  the 
evaporation  test  was  25  per  cent.  As  a  result  of  an 
investigation  undertaken  by  the  Boston  Manufac- 
turers' Mutual  Fire  Insurance  Company,  all  oils  of 
this  type  were  driven  out  of  use  within  a  year. 

Specifications  for  Lubricants.  There  seems  to  be  a 
tendency,  more  particularly  in  England,  not  to  use 
specifications  in  purchasing  oils.  Taggart 1  makes  the 
following  rather  remarkable  statement:  "At  present 
one  seldom  meets  with  such  a  specification  and  it  is 
certainly  of  little  credit  to  the  engineer  who  issues  one. 
To  the  manufacturer  of  the  oil  it  may  be  important, 
but  to  the  engineer  it  is  useless  and  the  wise  ones  are 
beginning  to  realize  the  fact."  The  fact  is  that  the 
manufacturers  control  their  product  by  these  very 
chemical  and  physical  tests;  if  they  are  "important" 
to  the  manufacturer,  they  certainly  are  of  equal  im- 
portance to  an  engineer,  who  should  be  "wise"  enough 

1  Power,  July,  1906,  page  434. 


ENGINE-ROOM    CHEMISTRY 


to  know  what  they  mean  and  how  they  are  applied. 
This  is  in  line  with  the  remark  of  an  oil  dealer  to  the 
author  that  a  course  of  instruction  in  oil  testing  was 
going  to  make  his  work  more  difficult. 

The  writer  is  inclined  to  believe  that  the  objection  to 
specifications  for  oils  is  fostered  by  certain  oil  com- 


FIG.  44.  —  New  York   State 
Tester 

panics,  and  he  finds  it  difficult  to  believe  that  it  is  not 
for  ulterior  purposes. 

Specifications  for  lubricants  are  issued  by  many  rail- 
roads, both  in  America  and  in  Germany,  and  by  tex- 
tile, paper,  brass,  iron,  steel  and  other  manufacturers, 
also  by  municipalities  for  their  water  works  and  elec- 


MINERAL    OILS  151 

trie  light  plants;  in  fact,  they  are  employed  by  nearly 
all  large  users  of  oil.  The  introduction  of  specifica- 
tions is  usually  followed  by  a  decided  drop  in  the  ex- 
pense for  oil.  Specifications,  particularly  for  oils  ^or 
railroad  work,  will  be  found  in  the  author's  "Hand- 
book of  Oil  Analysis,"  and  pp.  180  to  182  of  this  book. 

Testing  of  Burning  Oils.  The  chief  tests  to  be  ap- 
plied to  this  class  of  oils  are  the  flash  and  fire  tests, 
specific  gravity  and  sulphuric  acid  test. 

In  making  the  Flash  Test,  three  different  types  of 
testers  are  used:  (i)  the  open  or  Tagliabue  tester,  in 
which  the  cup  containing  the  oil  is  not  covered  or 
closed,  but  is  freely  open  to  the  air;  (2)  the  covered 
or  New  York  State  tester,  in  which  the  cup  is  covered 
with  a  glass  cover  containing  two  holes;  and  (3)  the 
closed  or  Abel  tester  in  which  the  oil  is  heated  in  a 
tightly  closed  cup  which  is  opened  momentarily  for 
the  introduction  of  the  testing  flame. 

The  New  York  State  tester  consists  of  a  copper  oil 
cup  D  (Fig.  44),  holding  about  10  ounces  (the  quan- 
tity usually  contained  in  a  lamp)  and  heated  in  a  water- 
bath  by  a  small  Bunsen  flame.  The  cup  is  provided 
with  a  glass  cover  C,  carrying  a  thermometer  B  and 
a  hole  for  the  insertion  of  the  testing  flame  —  a  small 
gas  flame  J-inch  in  length. 

The  regulations  of  the  New  York  State  Board  of 
Health  1  stipulate  that  the  test  shall  be  applied  accord- 
ing to  the  following  directions: 

"Remove  the  oil-cup  and  fill  the  water-bath  with  cold  water  up 
to  the  mark  inside.  Replace  the  oil-cup  and  pour  in  enough  oil  to 

1  Report  of  the  New  York  State  Board  of  Health,  1882,  page  495. 


152  ENGINE-ROOM    CHEMISTRY 

fill  it  to  within  one-eighth  of  an  inch  of  the  flange  joining  the  cup  and 
the  vapor-chamber  above.  Care  must  be  taken  that  the  oil  does  not 
flow  over  the  flange.  Remove  all  air-bubbles  with  a  piece  of  dry 
paper.  Place  the  glass  cover  on  the  oil-cup,  and  so  adjust  the  ther- 
mometer that  its  bulb  shall  be  just  covered  by  the  oil. 

"If  an  alcohol  lamp  be  employed  for  heating  the  water-bath,  the 
wick  should  be  carefully  trimmed  and  adjusted  to  a  small  flame.  A 
small  Bunsen  burner  may  be  used  in  place  of  the  lamp.  The  rate  of 
heating  should  be  about  two  degrees  per  minute,  and  in  no  case  ex- 
ceed three  degrees. 

"As  a  flash-torch,  a  small  gas  jet  one-quarter  of  an  inch  in  length 
should  be  employed.  When  gas  is  not  at  hand  employ  a  piece  of 
waxed  linen  twine.  The  flame  in  this  case,  however,  should  be  small. 

"When  the  temperature  of  the  oil  has  reached  85  degrees  Fahr., 
the  testings  should  commence.  To  this  end  insert  the  torch  into  the 
opening  in  the  cover,  passing  it  in  at  such  an  angle  as  to  clear  well 
the  cover,  and  to  a  distance  about  half-way  between  the  oil  and 
the  cover.  The  motion  should  be  steady  and  uniform,  rapid  and 
without  any  pause.  This  should  be  repeated  at  every  two  degrees' 
rise  of  the  thermometer  until  the  thermometer  has  reached  95  degrees, 
when  the  lamp  should  be  removed  and  the  testings  should  be  made 
for  each  degree  of  temperature  until  100  degrees  is  reached.  After 
this  the  lamp  may  be  replaced  if  necessary  and  the  testings  continued 
for  each  two  degrees. 

"The  appearance  of  a  slight  bluish  flame  passing  entirely  over 
the  surface  of  the  oil  shows  that  the  flashing-point  has  been  reached. 

"In  every  case  note  the  temperature  of  the  oil  before  introducing 
the  torch.  The  flame  of  the  torch  must  not  come  in  contact  with 
the  oil. 

"The  water-bath  should  be  filled  with  cold  water  for  each  sepa- 
rate test,  and  the  oil  from  a  previous  test  carefully  wiped  from  the 
oil-cup." 

In  making  the  flash  test  it  should  be  borne  in  mind 
that  any  cause  liberating  the  vapor  quickly  from  the 
oil  lowers  the  flash-point:  such  causes  are:  (i)  rapid 
heating;  (2)  a  large  and  shallow  cup  from  which  the 


MINERAL    OILS  153 

evaporation  takes  place  quickly;  (3)  a  large  quantity 
of  oil  used  for  the  test ;  and  (4)  a  large  testing  flame  or 
one  too  frequently  or  closely  applied. 

The  results  obtained  with  this  apparatus  are  about 
five  to  eight  degrees"  lower  than  those  obtained  with 
open  cups.  This  cup  reproduces  more  closely  than  any 
other  the  conditions  prevailing  when  burning  the  oil  in 
lamps.  The  amount  of  oil  used  is  about  10  ounces,  the 
capacity  of  an  ordinary  lamp:  the  tester,  like  a  lamp, 
is  not  freely  open  to  the  air,  preventing  the  escape  of 
volatile  vapors.  This  escape  takes  place  with  open 
cups  and  consequently  the  results  obtained  with  them 
are  higher. 

The  Fire  Test  is  made  by  raising  the  cover  above  the 
cup  and  continuing  to  heat  the  oil  until  it  gives 
off  vapors  which  burn  continuously  when  ignited. 
It  is  usually  15  to  25  degrees  higher  than  the  flash- 
point. 

In  choosing  a  burning  oil,  one  of  a  high  flash-point 
rather  than  one  of  a  high  fire-point  should  be  selected, 
as  the  flash-  not  the  fire-point  determines  the  safety 
of  the  oil.  Oils  having  a  high  flash  test  are  sure  to 
have  a  high  fire  test ;  but  those  of  a  high  fire  test  may 
or  may  not  have  a  high  flash  test.  That  is,  in  only 
making  the  fire  test, -no  attention  is  paid  to  the  flash 
test,  and  the  dangerous  volatile  constituents  of  the  oil 
(naphtha)  escape  detection,  being  driven  off.  This 
was  well  illustrated  in  a  sample  of  fuel  oil  sent  to  the 
writer  for  test.  The  flash-point  was  60  deg.  F.  and 
the  fire-point  143  deg.:  had  the  fire-point  alone  been 
considered  it  would  have  been  regarded  as  a  safe  oil, 


154 


ENGINE-ROOM    CHEMISTRY 


whereas  the  flash-point  (60  deg.  F.)  showed  it  to  be 
dangerous.  Too  much  stress,  therefore,  cannot  be 
laid  on  the  flash  test,  which  should  be  at  least  1 10  deg. 
F.  (or  better,  120  deg.  F.),  remembering  that  a  safe  oil 
makes  safe  lamps.  Professor  Engler  states  that  no 
lamp  should  be  used  which  heats  the  oil  more  than 
10  deg.  F.  above  the  surrounding  atmosphere, 


FIG.  45.  —  Thurston's  Oil  Friction 
Testing  Machine 

The  Specific  Gravity  of  burning  oils  is  determined 
exactly  as  in  the  case  of  lubricating  oils. 

The  Sulphuric  Acid  Test  shows  the  degree  to  which 
an  oil  is  refined,  that  is,  the  extent  to  which  the  tarry 
and  ill-smelling  products  in  the  oil,  or  formed  during 
the  process  of  distillation,  have  been  removed  from 
the  oil.  It  is  made  by  shaking  100  grams  of  the  oil 


MINERAL    OILS  155 

with  40  grams  of  sulphuric  acid  of  1.73  sp.  gr.  for  two 
minutes  and  noting  the  color  of  the  acid  layers:  a 
suitably  refined  oil  should  give  little  or  no  color. 

Friction  Test.  By  this  is  meant  the  determination 
of  the  amount  of  power  required  to  overcome  the  re- 
sistance of  an  oil  when  applied  to  a  bearing.  The  oil 


FIG.  46.  —  Thurston's  Friction 
Testing  Machine 

is  tested  under  ideal  conditions,  with  a  shaft  and  boxes 
as  nearly  perfect  as  mechanical  skill  can  make  them, 
with  the  feed  of  oil,  the  temperature  of  and  pressure  on 
the  bearing  even,  regular,  and  under  complete  control. 
The  small  Thurston  machine  shown  in  Figs.  45  and 
46  will  give  an  idea  of  the  principle  and  construction 


156  ENGINE-ROOM    CHEMISTRY 

of  these  machines.  It  consists  of  the  testing-shaft  or 
journal  F,  i%  in.  long  by  i£  in.  in  diameter,  and 
the  bronze  bearings  G  G ,  the  pressure  of  which  on  the 
shaft  can  be  regulated  by  the  coiled  spring.  The 
amount  of  pressure  is  shown  by  the  index  M:  a  ther- 
mometer in  Q  indicates  the  temperature  of  the  bearing. 
The  journal  is  rotated,  by  means  of  the  step-pulley  C, 
in  the  direction  of  the  arrow;  this  causes  a  displacement 
of  the  pendulum  G  K,  containing  the  spring  /  along 
the  arc  P  P' '. 

The  amount  of  displacement  along  this  arc  measures 
the  friction  of  the  oil,  being  large  with  great  friction 
and  small  with  good  lubricants.  The  arc  is  so  gradu- 
ated that,  dividing  the  reading  by  the  pressure  shown 
by  the  index  M,  the  coefficient  of  friction  is  given. 
This  machine  is  designed  for  testing  the  lighter  oils:  a 
larger  size  of  this  machine  is  made  with  journal  3^  in. 
in  diameter  and  7  in.  long  for  heavy  lubricants  and 
railroad  work. 

The  writer  is  inclined  to  question  the  value  of  the 
friction  test  for  practical  purposes:  he  believes  that 
equally  good  or  better  results  can  be  obtained  by  com- 
paring the  flash,  fire,  gravity,  and  viscosity  tests  of  the 
oil  in  question  with  those  of  one  that  has  given  satis- 
factory results  in  practice. 

This  holds  strictly  true  only  of  oils  coming  from  the 
same  field  or  part  of  the  country;  Texas,  Ohio  and 
Pennsylvania  oils,  or  oils  having  an  asphaltic  base,  can- 
not be  compared  with  those  having  a  paraffin  base,  nor 
those  carrying  sulphur  with  those  not  carrying  sulphur. 


VII 


ANIMAL  AND   VEGETABLE  OILS  — GENERAL 
CONSIDERATIONS    REGARDING    LUBRICANTS 

THE  petroleum  oils  considered  in  the  preceding  chap- 
ter are,  chemically  speaking,  hydrocarbons  —  com- 
posed solely  of  carbon  and  hydrogen  —  and  as  such, 
very  stable  bodies.  Their  formulas  are  very  simple, 
represented  by  the  general  expression  CnH2n+2.  Yet 
a  given  oil,  as  for  example  25-degree  paraffin,  can- 
not be  represented  by  figures,  as  C15H32  in  place  of  the 
n  and  n  +  2  in  the  formula  just  given,  the  reason  being 
that  the  petroleum  products  are  mixtures  of  bodies 
having  for  the  most  part  the  formula  given. 

Besides  containing  C15H32  it  most  likely  contains 
C12H26,  C13H28,  C16H34  and  others  up  to  Qo^,  or  even 
higher.  The  reason  for  this  is,  that  the  hydrocarbons 
given  boil  within  a  few  degrees  (27-36)  of  each  other 
and  cannot  be  separated  in  the  ordinary  process  of 
distillation,  very  careful  and  numerous  redistillations 
being  required. 

Animal  and  vegetable  oils,  besides  being  made  up  of 
carbon  and  hydrogen  like  the  preceding,  contain  oxy- 
gen, and  their  formulas  are  by  no  means  so  simple  as 
the  petroleum  oils;  they  are  salts,  organic  salts  of 

I57 


158  ENGINE-ROOM    CHEMISTRY 

organic  acids,  resembling  the  inorganic  salts  we  had 
in  some  of  the  early  chapters.  The  base  is  usually 

CH2OH 
glycerin  CHOH  or  C3H5(OH)3,  C3H5  being    trivalent 

CH2OH 

like  aluminum  (Al),  in  A1(OH)3,  and  the  acid  may  be 
stearic  (C17H35COOH),  palmitic  (C15H31  COOH),  or 
oleic  (C17H33COOH),  and  their  union  produces  (C17H35- 
COO)3C3H5,  stearine,  (C15H31COO)3C3H5,  palmitine, 
forming  the  solid  portions  of  fats,and  (C17H33COO)3C3H5, 
oleine,  the  liquid  portion.  These  glycerides,  as  these 
compounds  are  also  called,,  form  the  basis  of  most  of 
the  animal  fats  and  oils,  in  which  they  are  mixed  in 
varying  proportions.  The  differences  in  the  fats  or 
oils  are  produced  partly  by  the  different  quantities 
of  the  glycerides  named,  but  mainly  by  the  admixture 
of  small  quantities  of  the  glycerides  of  other  acids,  as 
butyric  in  the  case  of  butter,  linoleic  and  linolenic  in 
the  case  of  linseed,  and  other  drying  oils,  etc. 

That  the  fats  and  oils  are  really  salts,  as  has  been 
stated,  can  be  seen  from  their  behavior  with  caustic 
soda  or  potash,  which  converts  them  into  soap,  setting 
free  glycerin  at  the  same  time: 


+  3NaOH          =  C3H5(OH)3  +  sdr 

(sodium  stearate) 
Glyceryl  stearate    +  caustic  soda  =       glycerin    +       hard  soap 

This  class  of  oils  is  distinguished  from  the  hydrocarbon 
or  petroleum  oils  in  being  saponifiable  (there  is  no 
known  way  of  saponifying  the  petroleum  products), 
and,  when  heated,  in  breaking  up  or  "cracking"  into 


ANIMAL    AND    VEGETABLE    OILS  159 

acid  products,  instead  of  distilling  over  as  do  the  petro- 
leums. 

Vegetable  oils  are  divided  into  two  classes:  the  fatty 
or  fixed  oils  and  the  volatile  oils.  The  former  cannot 
be  distilled  without  decomposition,  are  not  volatile 
with  steam,  and  leave  a  fixed  stain  on  paper  or  cloth. 
The  volatile  or  essential  oils  distil  readily,  pass  over 
with  steam,  and  evaporate  completely  from  paper: 
these  are  the  bodies  which  give  the  characteristic  odor 
or  perfume  to  plants  and  flowers,  as  peppermint,  rose, 
lemon,  etc.  Their  composition  is  very  complex,  being 
mixtures  of  organic  salts  of  organic  acids  similar  to  the 
fatty  oils,  as  well  as  acids,  alcohols,  ketones,  hydro- 
carbons, etc.;  oil  of  peppermint  contains  no  less  than 
fifteen  different  compounds. 

Oil  is  found  in  all  parts  of  animals  and  vegetables, 
although  more  is  contained  in  certain  parts  than  in 
others.  In  land  animals  the  fat  occurs  on  the  back, 
abdomen,  and  upper  parts  of  the  legs;  in  fish,  around 
the  body,  as  the  blubber  of  the  whale,  in  the  head  with 
the  blackfish  and  sperm  whale,  throughout  the  whole 
body,  as  in  the  menhaden,  and  in  the  liver  as  with  the 
codfish  and  shark. 

With  vegetables,  oil  is  mostly  found  in  the  seed,  al- 
though with  the  essential  or  volatile  oils  they  occur  in 
the  flower  as  with  the  rose,  in  the  bark  as  with  cinna- 
mon, and  in  the  root  as  with  sassafras. 

These  oils  are  contained  in  cells  composed  of  animal 
membranes  or  cellulose,  and  to  obtain  the  oil  the  cells 
must  be  ruptured;  this  is  usually  done  by  heat  in  the 
case  of  animal,  and  with  vegetable  oils  by  grinding 


160  ENGINE-ROOM    CHEMISTRY 

and  pressure.  The  membranes  containing  oil  soon 
putrefy  on  standing,  causing  the  oil  to  turn  rancid  and 
have  a  bad  odor;  consequently,  animal  oils  should  be 
rendered  as  soon  as  possible. 

The  animal  fat  is  cut  up  into  small  fragments  and 
filled  into  large  digesters  or  autoclaves,  heated  with 
direct  steam.  The  apparatus  is  filled  and  discharged 
by  manholes  at  the  top  and  bottom.  On  steam,  at  50 
pounds  pressure,  being  admitted,  the  cell  walls  are 
broken  down  and  the  fat  melted  which  flows,  together 
with  the  water,  to  the  bottom  of  the  apparatus. 
The  gases  evolved,  together  with  some  steam  which 
is  condensed,  pass  to  a  chimney  or  sewer:  after  a  few 
hours'  heating  the  steam  is  shut  off,  the  pressure  re- 
moved, and  the  autoclave  allowed  to  stand  to  sep- 
arate the  oil  from  the  water:  the  separation  can  be 
determined  by  means  of  cocks  at  various  heights  upon 
the  autoclave.  When  this  has  taken  place,  the  water 
is  drawn  of?  as  completely  as  possible  through  these 
cocks,  and  the  oil  through  another.  The  animal  tis- 
sue (cell  walls  or  membranes),  "scraps"  or  "crack- 
lings" are  discharged  through  the  bottom  manhole. 
These  cocks  serve  also  as  exits  for  the  water  used  in 
washing  the  fat  after  it  is  packed  in  the  autoclave. 

With  the  vegetable  oils  the  seeds,  hulled  in  some 
cases,  are  crushed  by  rollers  or  edge-runners,  rupturing 
the  oil-cells,  the  resulting  mass  being  steamed  or 
"cooked,"  to  complete  the  rupture  and  render  the  oil 
more  fluid,  and  then  pressed  in  duck  or  horsehair 
bags,  in  a  hydraulic  press.  This  consists  of  a 
framework  supporting  the  top  against  which  the  bags 


ANIMAL    AND    VEGETABLE    OILS  161 

are  pressed  by  the  ram,  forced  out  of  its  cylinder 
by  the  pressure  of  water  or  oil  which  is  pumped  into 
it.  Oil  obtained  by  cold  and  moderate  pressing  is  the 
best.  The  yield  is  small,  and  after  pressing  in  this 
manner  the  press  is  inclosed  and  heated  by  steam,  and 
the  pressure  increased  with  a  corresponding  increase 
in  yield. 

Besides  these  presses,  wedge,  screw,  knuckle-joint, 
lever  and  eccentric  presses  are  used. 

As  was  noted  in  a  preceding  paragraph,  vegetable 
oils  can  be  prepared  by  dissolving  them  out  from  the 
crushed  mass  with  naphtha,  carbon  bisulphide  or  tetra- 
chloride.  To  this  end  the  crushed  seeds  are  filled  into 
boiler-iron  extractors  like  the  autoclave,  provided 
with  false  bottoms,  and  the  solvent,  as  naphtha, 
caused  to  circulate  through  the  mass,  dissolving  out 
the  oil.  The  solution  is  then  heated,  the  solvent  dis- 
tilled off,  leaving  the  oil,  and  the  condensed  solvent  can 
be  used  again.  A  larger  yield  of  oil  is  obtained  by  this 
method,  but  it  contains  more  impurities  as  gums, 
gelatinous  matters,  etc.,  for  the  naphtha  dissolves  these 
as  well  as  the  oil.  Furthermore,  the  odor  of  the  sol- 
vent is  difficult  to  remove  from  the  oil  completely. 
The  residue  left  in  the  extractors,  containing  less  oil,  is 
not  as  valuable  for  cattle  feed  as  the  press  cake,  and  can 
only  be  used  as  a  fertilizer  or  fuel.  The  plant  for  this 
process  is  more  complicated  and  expensive,  and  more 
dangerous  as  a  fire  risk. 

The  oils  as  freshly  expressed  or  rendered,  are  often 
dark  in  color  or  contain  resinous,  gummy,  or  gelati- 
nous matter,  fatty  acids  and  water,  and  require  to  be 


1 62  ENGINE-ROOM    CHEMISTRY 

refined  or  clarified.  The  treatment  varies  with  the  oil: 
with  cottonseed,  whale,  and  sperm  oils  they  are  treated 
with  caustic  soda  lye  which  combines  with  the  color 
and  saponifies  the  fatty  acids,  the  soap  thus  formed 
carrying  down  the  gummy  matters  as  "foots."  Some 
of  the  animal  oils,  as  lard,  are  in  addition  treated  with 
compressed  air  and  fuller's  earth  to  improve  the  color. 
Certain  other  oils  are  bleached  with  acids  and  bichro- 
mate of  potassium  or  sodium  peroxide;  oftentimes,  as 
with  linseed  oil,  water  and  mucilage  are  removed  by 
allowing  the  oil  to  settle  for  twelve  to  eighteen  months, 
becoming  an  "aged"  or  "varnish  oil."  Besides  this 
artificial  means,  oils  are  bleached  by  exposure  to  sun- 
light in  shallow  tanks. 

Examination  of  an  Animal  or  Vegetable  Oil.  —  In 
examining  an  unknown  oil  the  analyst  should  ascer- 
tain all  possible  facts  about  it,  its  cost,  its  source,  and 
the  use  for  which  it  is  intended.  There  is  unfortu- 
nately no  such  number  of  specific  tests  for  the  various 
oils  as  there  are  for  the  various  metals:  while  it  is  easy 
to  say  positively  that  a  certain  metal  is  present  or 
absent,  the  same  cannot  be  said  of  many  of  the  oils. 
We  can  be  absolutely  sure  of  the  presence  of  cotton- 
seed, sesame,  palm,  rosin  and  mineral  oils,  and  reason- 
ably certain  of  peanut,  rape,  castor,  and  sperm,  but 
can  only  have  more  or  less  strong  suspicions  as  to  the 
presence  or  absence  of  most  of  the  others. 

The  fact,  too,  that  crops  vary  in  quality  from  year 
to  year,  cannot  but  have  its  influence  upon  the  qfuality 
of  vegetable  oils  produced.  Whereas  in  the  case  of  an 
inorganic  compound,  like  soda  ash,  we  can  require  that 


ANIMAL    AND    VEGETABLE    OILS  163 

it  must  contain  58  per  cent,  of  oxide  of  sodium,  with 
less  than  i  per  cent,  variation  either  way,  we  cannot 
prescribe  such  definite  specifications  for  oils,  for  the 
reason  just  stated,  i.e.,  the  variation  in  genuine  oils,  on 
account  of  the  change  due  to  the  season,  wet  or  dry, 
cold  or  hot,  or  the  variety  of  the  plant  or  tree  —  there 
are  300  varieties  of  olive-trees  -in  Italy  alone.  These 
influences  change  the  "constants,"  like  the  specific 
gravity,  Maumene  figure,  etc.,  which  are  our  guides  for 
the  determination  of  the  amount  of  adulteration  of  an 
oil.  For  example,  the  Maumene  figure  for  olive-oil 
varies  from  35  to  47  degrees  C;  consequently,  if  we 
find  a  figure  of  44  degrees,  there  are  three  possibilities : 
first,  that  the  oil  is  genuine;  second,  that  it  is  an  oil 
originally  of  a  figure  of  47  degrees  which  has  been  adul- 
terated with  an  oil  of  lower  Maumene  figure;  or,  third, 
that  the  original  figure  was  41  degrees  and  it  has  been 
adulterated  with  an  oil  of  higher  Maumene  figure.  As 
to  which  of  these  is  correct,  we  must  be  guided  by  other 
"constants"  and  special  tests.  There  is  a  variation  of 
^|  or  27  per  cent,  in  these  "constants";  consequently, 
the  determination  of  the  percentage  of  one  oil  in  an- 
other may  not  be  accurate  within  about  14  per  cent. 
On  the  other  hand,  it  should  be  noted  that  the  sensi- 
tiveness of  chemical  methods  permits  the  carrying  out 
of  the  processes  for  the  determination  of  these  "con- 
stants" within  at  least  i  per  cent,  or  even  less. 

Considering  the  items  of  cost,  source  and  use,  the 
cost,  compared  with  current  prices,  will  give  an  idea  of 
the  kind  of  oil  if  it  be  uncompounded:  it  is  not  usual 
to  find  an  expensive  oil  mixed  with  one  of  lower  price, 


164  ENGINE-ROOM    CHEMISTRY 

unless  in  certain  lubricants.  The  source  or  kind  of 
an  oil  will  give  an  idea  of  the  possible  adulter- 
ants, and  also  of  the  tests  and  constants  to  which 
it  should  respond.  If  the  source  or  kind  of  oil  be 
not  known,  the  use  to  which  the  oil  is  to  be  put 
is  of  material  help  in  determining  its  composition: 
for  example,  the  paint  oils  are  linseed,  menhaden 
("p°gy")>  ani  in  some  cases,  corn;  the  currying 
oils  are  neatsfoot  and  "cod";  the  burning  oils,  lard, 
sperm,  and  rape. 

Tests  for  Animal  and  Vegetable  Oils.  —  Physical 
tests.  The  smell  of  an  oil  reveals  much  to  the  expert 
regarding  its  composition;  and  if  the  amateur  will 
take  the  trouble  to  make  a  collection  of  samples 
of  genuine  oils  for  comparison  he  will  find  them 
very  valuable  in  this  connection.  The  odor  is  best 
taken  by  warming  the  oil  in  a  small  beaker,  or  by 
rubbing  a  small  quantity  of  the  oil  between  the 
thumb  and  finger  and  smelling  them.  Marine  animal 
oils  are  readily  detected  by  their  strong  "fishy"  odor, 
while  neatsfoot,  tallow,  lard,  olive,  rosin,  and  linseed 
oils  have  each  a  well-marked  and  easily  distinguish- 
able odor.  Many  of  the  statements  just  made,  apply 
with  equal  force  to  the  taste  of  oils,  rape  oil  having 
a  harsh,  unpleasant  taste,  and  whale  oil  a  nutty 
flavor. 

The  color  of  an  oil  is  not  to  be  relied  upon  for  identi- 
fication, as  oils  may  be  colored  reddish  or  greenish  by 
the  oleates  of  iron  or  copper:  the  "bloom,"  fluores- 
cence or  peculiar  bluish  or  greenish  streak  seen  on  the 
sides  of  a  vial  containing  mineral  oil,  is  proof  positive 


ANIMAL    AND    VEGETABLE    OILS  165 

of  the  presence  of  a  hydrocarbon  or  petroleum  oil; 
this  can  be  further  shown  by  putting  a  few  drops  of 
the  oil  on  a  piece  of  hard  rubber  or  other  black  sur- 
face and  observing  the  bluish  color. 

Specific  Gravity.  This  is  determined  in  the  same 
way,  with  a  hydrometer,  as  with  mineral  oils:  if  the 
instrument  be  graduated  in  Baume  degrees  only,  the 
reading  should  be  converted  into  specific  gravity  re- 
ferred to  water,  as  that  is  the  way  in  which  the  animal 
and  vegetable  oils  are  designated.  Care  should  be 
taken  to  note  the  temperature  of  the  oil,  which  should 
be  60  deg.  F.,  as  in  the  case  of  petroleum,  and  for  every 
degree  Fahrenheit  above  60  add  0.00035  to  the  observed 
specific  gravity.  Suppose,  for  example,  the  hydro- 
meter shows  a  reading  of  23.75  deg.  B.  at  7°  deg.  F-: 
required  the  specific  gravity  of  the  oil  in  question  at 
60  deg.  F.?  According  to  Table  X  in  the  Appendix 
23  deg.  B.  =  0.9150  and  24  deg.  =  0.9090,  a  differ- 
ence of  0.0060  for  i  degree  Beaume:  0.75  deg.  B.  the 
excess  above  23  deg  X  0.006  =  0.0045.  0.9150- 
0.0045  =  0.9105  deg.  That  is,  23.75  deg.  B.  =  0.9105 
sp.  gr.  At  70  deg.  F.  for  every  degree  Fahrenheit 
above  60,  0.00035  ls  to  ^e  added,  or  0.0035  for  70—60 
=  10  degrees.  0.9105  +  0.0035  =  0.9140,  the  specific 
gravity  of  the  oil  at  60  deg.  F.  The  fact  that  the 
hotter  an  oil  is  the  lighter  it  is,  should  not  be  for- 
gotten, and  also  the  reverse  of  this  statement.  Table 
XI,  Appendix,  shows  the  specific  gravity  of  certain 
oils  also  expressed  in  degrees  Baume,  and  their 
weights  per  gallon  and  per  cubic  foot. 

Valenla  Test.     This  depends  upon  the  solubility  of 


1 66  ENGINE-ROOM    CHEMISTRY 

the  various  oils  in  glacial  acetic  acid.1  Instead  of  de- 
termining how  much  acid  is  necessary  to  dissolve  a 
certain  quantity  of  oil,  equal  quantities  of  oil  and  acid 
are  mixed,  warmed,  then  cooled  and  the  temperature 
at  which  the  oils  become  turbid  is  noted.  The  test 
bears  the  name  of  the  discoverer.  To  perform  it,  suffi- 
cient oil  is  poured  into  a  test-tube  to  fill  it  about  an 
inch  in  depth,  the  hight  to  which  it  rises  being  indicated 
by  the  thumb-nail,  and  a  quantity  of  glacial  acetic 
acid  equal  to  the  oil  poured  in  upon  it,  until  it  reaches 
the  hight  shown  by  the  thumb-nail.  A  rather  light 
chemical  thermometer  —  usually  graduated  in  Centi- 
grade degrees  —  serves  to  mix  the  oil  and  acid,  and 
the  mixture  is  heated  over  an  alcohol  or  gas  lamp  until 
it  becomes  clear;  it  is  allowed  to  cool  and  the  tem- 
perature at  which  it  becomes  cloudy  is  noted;  it  is 
slightly  warmed  again  until  clear  and  the  cooling  is 
repeated.  The  readings  should  coincide  within  half  a 
degree.  Castor  oil  is  soluble  at  the  ordinary  tempera- 
ture, while  rape  seed  is  usually  insoluble  at  the  boiling- 
point  of  the  acid;  the  temperatures  at  which  some  oils 
become  turbid  are  shown  in  Table  XII,  Appendix. 

Elaidin  Test.  This  test  depends  on  the  fact  that 
certain  oils,  rich  in  olein,  like  lard  and  neatsfoot,  are 
changed  by  nitrous  acid  into  a  solid  body  having  the 
same  composition — elaidin.  It  serves  to  distinguish 
between  the  non-drying,  semi-drying,  and  drying  oils: 
when  submitted  to  this  test,  the  non-drying  oils  usu- 

1  Glacial  acetic  acid  is  so  strong  that  it  freezes  at  17  deg.  C.  and  boils  at  118  de- 
grees Centigrade.  Care  should  be  used  not  to  get  it  upon  the  person,  as  it  blisters 
severely. 


ANIMAL    AND    VEGETABLE    OILS  167 

ally  form  a  solid  cake,  so  solid  in  fact  that  the  vessel 
and  contents  can  be  lifted  by  the  rod  congealed  in  the 
cake  of  elaidin;  the  semi-drying  oils  form  a  more  or 
less  pasty  mass,  while  the  drying  oils  form  a  liquid  mass 
with  clots  floating  about  in  it.  The  test  is  performed  as 
follows:  five  grams  of  the  oil  are  weighed  out  into  a 
cordial  glass  (a  small  goblet  about  three  inches  high) 
on  the  horn  pan  scales  and  seven  grams  (about  5'cc.) 
nitric  acid  of  1.34  sp.  gr.  weighed  into  it,  and  the  glass 
immersed  in  a  pan  of  iced  water,  at  50  to  60  degrees 
Fahrenheit,  to  within  half  an  inch  of  the  top.  After 
about  ten  minutes  two  pieces  of  copper  wire,  No.  15, 
B.  &  S.  gage,  |  inch  long  are  dropped  in,  and  the  oil 
and  acid  stirred  together  with  a  short  glass  rod,  with 
an  up-and-down  as  well  as  a  rotary  movement,  so  as 
to  mix  the  oil,  acid,  and  evolved  gas  thoroughly.  When 
the  wire  has  dissolved,  add  two  more  pieces  and  stir  as 
before:  this  should  furnish  gas  enough,  if  the  liquid  has 
been  kept  cool  and  the  stirring  has  been  thorough.  At 
the  end  of  the  first  hour  pure  lard  will  usually  show 
flakes  of  a  wax-like  appearance,  and  upon  standing 
without  disturbance  for  another  hour  at  the  same 
temperature,  the  oil  will  have  changed  to  a  hard, 
solid,  white  cake.  Most  of  the  fish  and  seed  oils  yield 
a  pasty  or  buttery  mass  separating  from  a  fluid  por- 
tion, whereas  olive,  lard,  sperm,  and  sometimes  neats- 
foot  oil,  yield  a  solid  cake.  To  make  sure  of  the 
manipulation,  a  test  should  be  made  at  the  same  time 
and  in  the  same  way  with  an  oil  of  undoubted  purity 
-lard  oil  for  example:  if  a  hard  cake  be  obtained  in 
the  latter  case,  and  a  buttery  mass  with  the  oil  under 


l68  ENGINE-ROOM    CHEMISTRY 

examination,  it  is  very  good  evidence  that  the  latter 
is  either  a  seed  oil  or  an  olive,  lard,  or  sperm  oil, 
adulterated  with  a  seed  or  mineral  oil. 

Tine  Maumene  Test  (pronounced  Momenay),  or 
heating  test  with  sulphuric  acid,  is  one  of  the  most 
important  tests  to  determine  the  variety  or  kind  of 
an  oil:  it  possesses  the  advantage  that  it  requires  no 
complicated  apparatus  and  is  simple  in  execution.  The 
underlying  principle  is,  that  when  oils  are  mixed  with 
strong  sulphuric  acid,  heat  is  produced  and  the  quan- 
tity of  heat  so  produced  is  characteristic  of  the  various 
oils. 

The  apparatus  required  consists  of  a  rather  tall  and 
narrow  beaker  holding  about  five  ounces  (150  cc.) 
which  is  packed  in  a  tin  can,  agate-ware  cup  or  larger 
beaker,  with  dry  cotton  waste  or  hair  felt,  the  pack- 
ing being  perhaps  an  inch  thick;  a  light  thermometer 
graduated  from  o  to  150  or  200  deg.  C,  a  lo-cc. 
graduate  and  pair  of  horn  pan  scales  complete  the  outfit. 

The  test  is  conducted  as  follows:  The  beaker  is  taken 
out  from  its  packing  —  disturbing  it  as  little  as  pos- 
sible —  weighed  on  the  scales,  and  fifty  grams  of  oil 
weighed  into  it,  to  within  two  drops,  the  beaker  re- 
placed in  its  jacket,  the  thermometer  inserted  in  the 
oil,  and  its  temperature  noted  down.  Ten  cubic  cen- 
timeters of  strong  sulphuric  acid  are  measured  out  in 
the  graduate  and  gradually  run  into  the  oil,  it  being 
stirred  at  the  same  time  with  the  thermometer,  and 
the  graduate  allowed  to  drain  about  five  seconds  —  that 
is,  while  one  counts  ten.  The  stirring  is  continued 
until  no  further  increase  in  temperature  is  noted.  The 


ANIMAL    AND    VEGETABLE    OILS  169 

highest  point  at  which  the  thermometer  remains  con- 
stant for  any  appreciable  time  is  observed,  and  the 
difference  between  this  and  the  original  temperature  of 
the  oil  is  the  "rise  of  temperature." 

The  mixture  of  oil  and  acid  is  thrown  on  the  ash-heap, 
the  thermometer  and  beaker  are  carefully  wiped  free 
of  oil  with  cotton  waste;  and  the  jacket  is  allowed  to 
cool  down  to  the  original  temperature,  when  the  ap- 
paratus is  again  ready  for  use.  A  duplicate  test  should 
always  be  made  and  the  results  should  agree  within  2  or 
3  per  cent. :  that  is,  with  a  rise  of  40  deg.  C.  the  results 
of  the  two  experiments  should  differ  only  by  one  degree. 
Since  the  rise  of  temperature  varies  with  the  strength 
of  the  acid,  to  secure  uniformity,  the  experiment  should 
be  repeated,  using  water  instead  of  oil,  and  the  rise  of 
temperature  here  obtained,  used  to  divide  the  rise  of 
temperature  with  the  oil,  and  the  result  multiplied  by 
one  hundred.  This  is  called  the  "specific  temperature 
reaction."  The  acid  used  should  be  the  strongest  ob- 
tainable and  should  show  a  specific  gravity  of  1.84. 
Fuming  sulphuric  acid  should  not  be  used. 

In  case  the  test  is  to  be  applied  to  a  drying  or  semi- 
drying  oil,  it  should  be  diluted  with  an  equal  weight  of 
petroleum  oil  and  then  thoroughly  mixed:  the  "rise  of 
temperature"  is  in  this  case  the  rise  of  temperature  of 
the  mixture,  minus  half  the  rise  of  temperature  of  fifty 
grams  of  mineral  oil,  multiplied  by  two. 

For  concordant  results,  the  conditions  should  be 
the  same,  and  the  same  apparatus  should  be  used. 
The  percentage  of  one  oil  in  a  mixture  of  two  oils 
can  be  found  by  the  following  formula: 


170  ENGINE-ROOM    CHEMISTRY 

Let  x  =  percentage  of  the  one  oil  and  y  of  the  other;  further,  m  = 
Maumene  value  of  pure  oil  x,  and  n  of  pure  oil  y,  and  /  of  oil  under 

ioo(7  -  n) 
examination,  then  x  =  — 

m  —  n 

To  illustrate  the  application  of  this  formula,  suppose 
we  have  an  olive-oil  adulterated  with  cottonseed:  the 
sample  in  question  has  a  Maumene  figure  of  60.  We 
see  from  Table  XII,  Appendix,  that  cottonseed  oil  has 
a  Maumene  figure  of  76  and  olive-oil  one  of  35.  Then, 

substituting  in  the  formula,  x  =  100  (—7—     -M  =  61 

per  cent.  That  is,  there  is  about  60  per  cent,  of  cot- 
tonseed oil  in  the  olive-oil.  As  with  other  oils,  it  is 
advisable  to  make  a  test  with  an  oil  of  known  purity. 
Halpben's  test  for  Cottonseed  Oil.  This  depends  upon 
the  fact  that  this  oil  contains  a  fatty  acid,  which  com- 
bines with  sulphur  giving  a  colored  compound.  The 
apparatus  needed  is  a  large  test-tube  seven  or  eight 
inches  long  by  one  inch  in  diameter,  fitted  with  a 
tube  f  inch  in  diameter  and  about  five  or  six  feet 

o 

long,  to  serve  as  a  condenser  for  the  alcohol  which 
is  used  in  the  test.  To  join  or  fit  the  long  tube  to 
the  test-tube,  soften  a  good  cork  that  fits  the  test- 
tube,  by  rolling  it  under  a  board  on  the  bench:  with 
a  6-inch  or  y-inch  round  file,  bore  a  hole  through 
the  cork  from  the  small  end,  file  this  out  using  larger 
round  files  until  the  long  tube  fits  snugly-into  the  cork. 
Before  trying  the  tube  in  the  cork,  round  the  sharp 
edges  with  a  file,  otherwise  they  will  cut  the  cork  and 
make  a  poor  fit;  if  the  tube  be  wet,  it  will  slip  or  twist 
into  the  cork  much  better.  Besides  this,  an  agate-ware 


ANIMAL    AND    VEGETABLE    OILS  171 

cup  holding  brine,  and  means  of  heating  it,  and  a  water- 
bath  are  required.  The  chemicals  or  reagents  needed 
are  amyl  alcohol  (fusel  oil)  and  a  i^-per-cent.  solution 
of  sulphur  in  carbon  bisulphide.  This  should  not  be 
opened  near  a  fire  or  flame,  as  it  is  very  inflammable. 

To  make  the  test  about  two  or  three  teaspoonfuls 
(10-15  cc.)  of  the  melted  fat.  or  oil  (the  exact  quan- 
tity makes  no  difference)  are  heated  with  an  equal 
volume  of  the  amyl  alcohol  and  of  the  carbon  bisul- 
phide solution  of  sulphur,  with  occasional  shaking,  in 
the  water-bath,  and  after  the  violent  boiling  has 
ceased,  in  the  brine  bath  at  about  220-230  deg.  F. 
for  forty-five  minutes  to  three  hours,  according  to  the 
quantity  of  cottonseed  oil  present,  the  tube  being  oc- 
casionally removed  and  shaken.  As  little  as  i  per 
cent,  will  give  a  crimson-wine  coloration  in  twenty 
minutes.  If  the  mixture  be  heated  too  long,  a  mis- 
leading brownish  red  color  due  to  burning  is  pro- 
duced. 

Test  for  Unsaponifiable  Oils  in  Animal  or  Vegetable 
Fats  and  Oils.  This  depends  upon  the  fact  that  when 
a  soap  solution  containing  unsaponified  oil  is  diluted 
with  water,  it  is  precipitated,  causing  an  opalescence 
or  turbidity.  Six  or  eight  drops  of  oil  are  boiled  two 
minutes  in  a  test-tube  with  a  teaspoonful  of  3-per-cent. 
alcoholic-potash  solution:  this  is  made  by  dissolving 
caustic  potash  in  ordinary  alcohol  or  wood  spirits. 
The  potash  makes  soap  of  the  oil,  and  to  this  soap  solu- 
tion distilled  water  is  gradually  added  (|  to  15  cc.), 
and  one  notices  whether  the  solution  remains  clear  or 
whether  a  turbidity  appears  which'  clears  on  the  ad- 


172  ENGINE-ROOM    CHEMISTRY 

dition  of  more  water:  even  i  per  cent,  of  mineral  oil 
may  be  detected  in  this  way. 

There  are  two  other  tests  which  "are  applied  to  these 
oils  which  require  considerable  experience  and  a  num- 
ber of  reagents  that  can  be  prepared  only  by  a  skilled 
chemist:  as  these  are  sometimes  referred  to  in  oil 
analysis  they  will  be  defined  here.  These  tests  are  the 
Saponification  Number  and  Iodine  Value.  By  the 
saponification  number  or  value  is  meant  the  number 
of  milligrams  of  potassium  hydrate  (KOH)  necessary 
to  saponify  one  gram  of  the  oil:  this  is  nearly  the 
same  for  many  oils,  averaging  193;  rape  has  a  num- 
ber of  178,  and  sperm  124-145.  The  number  is  mainly 
of  value  in  detecting  adulteration  of  animal  or  vege- 
table oils  with  petroleum  or  rosin  oils  which  are  not 
saponifiable. 

By  the  iodine  number  or  value  is  understood  the 
number  of  milligrams  of  iodine  absorbed  by  one  gram 
of  oil;  this  varies  from  176  with  linseed  to  8  with  cocoa- 
nut  oil.  This  can  be  used  the  same  as  the  Maumene 
figure  for  calculating  the  adulteration  in  an  oil. 

The  tests  to  be  applied  to  animal  or  vegetable  oils 
may  be  summarized  as  follows: 

Ascertain,  if  possible,  source,  intended  use,  and  cost. 
Note  color,  sediment,  and  bloom. 

Compare  odor  and  taste  with  genuine  samples. 

Determine  specific  gravity  with  hydrometer  (be 
careful  about  temperature). 

Make  the  Elaidin  and  Maumene  tests,  and  calculate 
from  the  latter  the  percentage  of  each  oil  present. 

If  cottonseed  be  suspected,  apply  the  Halphen  test. 


ANIMAL    AND    VEGETABLE    OILS  173 

SOURCE,  PROPERTIES  AND  USES  OF  SOME  OF  THE  MORE 
IMPORTANT  ANIMAL  AND  VEGETABLE  OILS. 

Castor  oil  is  obtained  by  pressing  castor  beans  which 
contain  about  50  per  cent,  of  oil.  It  is  a  colorless  or 
pale-greenish,  heavy,  thick,  and  viscous  oil.  It  is 
adulterated  with  blown  oils  (for  few  others  are  heavy 
enough  to  serve  as  adulterants),  such  as  linseed,  rape, 
or  cottonseed  and  rosin  oils.  These,  though  10  per 
cent,  be  present,  cause  a  turbidity  with  alcohol  with 
which  castor  oil  is  miscible  in  every  proportion.  Castor 
oil  is  employed  in  medicine,  in  the  manufacture  of 
Turkey-red  oil  ("sulphonated  oil"),  for  soap-making, 
illumination,  as  a  belt  dressing  and  on  steamships  as  a 
lubricant. 

Corn  or  mai^e  oil  is  obtained  by  pressing  the  germ  of 
the  corn  separated  in  the  manufacture  of  starch  or 
alcohol:  it  is  a  pale  to  golden-yellow  oil,  excelling  cot- 
tonseed oil  in  absorbing  oxygen  from  the  air.  It  is 
adulterated  with  mineral  and  rosin  oils  which  would  be 
shown  by  lowering  the  Maumene  value  and  in  the  case 
of  mineral  oil  by  the  lower  specific  gravity.  It  is  used 
as  an  adulterant  for  linseed  and  lard  oils,  for  painting, 
burning,  lubricating  and  soap-making,  and,  after 
treatment  with  sulphur  chloride,  as  a  waterproof  and 
belt  dressing,  and  a  substitute  for  rubber. 

Cottonseed  oil  is  prepared  by  pressing  the  seeds  of  the 
cotton  plant,  which  contain  about  25  per  cent,  of  oil. 
When  first  pressed,  it  is  ruby  red  or  black,  and  is  puri- 
fied by  treatment  with  caustic  soda,  carrying  down  the 
color  and  gelatinous  substances  as  "cottonseed  foots." 


174  ENGINE-ROOM    CHEMISTRY 

The  oil  thus  obtained  varies  in  color  from  white  to  deep 
yellow.  It  belongs  to  the  class  of  the  semi-drying  oils, 
slowly  absorbing  oxygen  from  the  air  and  "gumming," 
which  renders  it  less  valuable  as  a  lubricant.  Cotton- 
seed oil  is  rarely  adulterated:  it  however  serves  to  adul- 
terate other  oils,  where  its  presence  can  be  shown  by 
the  Halphen  test,  already  described.  Other  uses  are 
as  a  screw-cutting  oil,  for  soap-making,  and  as  a  salad 
and  cooking  oil  in  "Cottolene,"  "Cotosuet,"  etc. 

Horse  oil  is  prepared  by  rendering  dead  horses.  It 
varies  in  consistency  from  an  oil  to  a  grease,  and  in 
color  from  light  to  deep  yellow.  It  is  used  for  mixing 
with  and  adulterating  other  oils. 

Lard  oil  is  obtained  by  pressing  lard.  The  lard  is 
chilled,  brought  into  press-cloths  and_  pressed  in  screw 
or  chain  presses  at  a  pressure  of  about  four  tons  to  the 
square  inch,  yielding  from  40  to  60  per  cent,  of  oil. 
The  oil  is  valued  according  to  color,  which  varies  from 
reddish  brown  to  very  light  straw  yellow,  according 
to  the  lard  from  which  it  is  pressed:  oftentimes  the 
color  is  improved  by  refining  with  fuller's  earth.  The 
grades  in  the  market  are  Prime,  Pure,  Extra  No.  i, 
Crackling  Oil,  No.  i  and  No.  2,  Prime  being  the  best. 
The  odor  varies  from  almost  none  to  offensive  in  the 
No.  2  samples. 

Lard  oil  is  adulterated  with  cottonseed,  corn,  and 
neutral  petroleum  oils.  Cottonseed  would  be  shown 
by  the  Halphen  test  and  by  the  higher  Maumene  test 
(sulphuric  acid  test) :  should  the  oil  not  give  the  Hal- 
phen test,  but  show  a  high  Maumene  value,  it  is  an 
indication  of  the  presence  of  corn  oil.  Neutral  petro- 


ANIMAL    AND    VEGETABLE    OILS  175 

leum  would  be  shown  by  the  flash  test  and  a  low  Mau- 
mene  value;  ordinary  petroleum,  by  the  "bloom"  or 
fluorescence.  The  oil  is  used  as  a  screw-cutting  oil, 
for  burning  (signal  oil,  miner's  lamp  oil),  for  oiling 
textile  material  preparatory  to  spinning,  and  in  soap- 
making. 

Linseed  oil  is  prepared  from  flax-seed,  which  con- 
tains about  40  per  cent,  of  oil.  The  oil  receives  its 
name  from  the  locality  where  the  seed  is  grown,  as 
Calcutta  and  Western  oil.  It  is  of  golden  yellow  color 
and  pleasant  odor,  and  when  exposed  to  the  air  ab- 
sorbs oxygen,  forming  a  thin  film  of  a  gummy  insol- 
uble substance,  hence  its  use  as  a  paint  oil.  This  film 
is,  however,  quite  porous,  and  of  little  protection  unless 
it  carries  a  pigment  in  it.  Linseed  oil  is  thus  an  ex- 
ample of  a  drying  oil,  and  it  may  dry  so  rapidly  as  to 
produce  heat  and  cause  fire  by  spontaneous  combustion. 
Great  care  should  consequently  be  used  to  burn  up  all 
rags  or  waste  saturated  with  animal  or  vegetable  oils 
—particularly  linseed — not  even  saving  them  for  use 
on  the  following  day.  This  caution  does  not  apply  to 
mineral  oils  or  mixtures  of  the  above  oils  with  mineral 
oils  where  the  latter  constitute  half  the  volume  of  the 
mixture.  The  oils  which  are  liable  to  cause  sponta- 
neous combustion  are,  first,  the  drying  oils,  as  linseed 
and  menhaden;  the  semi-drying  oils  as  corn,  cotton- 
seed, and  rapeseed;  and  also  neatsfoot,  lard,  and  red 
oil. 

Linseed  oil  is  adulterated  with  corn,  cottonseed, 
menhaden,  and  rosin  oils,  all  of  which  retard  the  dry- 
ing tendency. 


1 76  ENGINE-ROOM    CHEMISTRY 

Neatsfoot  oil  is  obtained,  as  its  name  signifies,  from 
the  feet  of  neat  cattle,  that  is,  steers,  cows,  etc.  The 
hoofs  are  separated,  the  bones  of  the  feet  disjointed 
and  the  latter  boiled  with  water;  the  emulsion  is  al- 
lowed to  settle,  and  the  oil  which  rises  is  separated. 
As  is  the  case  with  all  oils,  that  which  is  obtained  with 
the  least  degree  of  heat  or  pressure  is  the  best.  It 
is  of  light-yellow  color,  bland  taste,  peculiar  odor, 
and  has  little  tendency  to  turn  rancid.  It  is  adulter- 
ated with  fish,  rapeseed,  cottonseed,  and  mineral  oils: 
the  first  three  would  raise  the  Maumene  figure;  the 
latter,  lower  it.  It  is  also  adulterated  with  other  hoof 
oils,  as  sheep-trotter  and  horsefoot  oil,  which  are  diffi- 
cult of  detection.  It  is  used  as  a  lubricant  by  itself 
or  compounded,  and  for  currying  leather. 

Rapeseed  oil.  This  oil  is  obtained  from  the  seeds  of 
plants  belonging  to  the  mustard  family  —  turnips  and 
their  varieties.  The  oil  is  pale  yellow  to  yellow,  of 
peculiar  odor  and  harsh  or  pungent  taste.  It  is  adul- 
terated with  cottonseed  and  refined  fish  oil :  the  former 
would  be  discovered  by  the  Halphen  test;  the  latter, 
by  the  odor.  It  is  used  as  a  lubricant,  more  par- 
ticularly in  Europe,  and  as  a  burning  oil. 

Rosin  oil  is  obtained  by  the  distillation  of  common 
rosin  in  stills  holding  about  thirty  barrels.  About  85 
per  cent,  of  oil  is  obtained;  this  is  distilled,  redistilled 
and  sometimes  distilled  again,  giving  "rosin  oil  first 
run,"  "second  run/'  "third  run,"  and  "fourth  run." 
A  small  quantity  of  rosin  spirits  is  obtained  at  the 
same  time.  "First  run"  is  employed  in  making  axle- 
grease,  in  oiling  leather  and  making  cements;  "second 


ANIMAL    AND    VEGETABLE    OILS  177 

run"  is  used  in  printing-ink  and  in  currying,  and  the 
"third"  and  "fourth  runs"  are  used  to  adulterate 
other  oils.  Rosin  oils  are  thick,  reddish-brown,  vis- 
cous liquids  of  high  specific  gravity,  0.981-0.987,  and 
peculiar  odor. 

Sperm  oil.  Real  sperm  oil  is  obtained  from  the  huge 
cavity  in  the  head  of  sperm  whales;  the  term  is  also 
applied  to  the  oil  obtained  by  trying  out  the  blubber, 
as  well  as  to  the  oil  from  the  Arctic  sperm  or  bottlenose 
whale.  The  crude  oil,  as  obtained  from  the  ships,  is 
packed  in  ice,  thus  chilling  it,  is  shoveled  into  bags 
and  pressed  after  the  manner  of  lard:  the  solid  part, 
after  refining,  forms  spermaceti,  and  the  liquid  portion, 
sperm  oil.  It  is  a  limpid  oil,  of  a  pale  yellow  color  and 
faint  odor,  and  is  one  of  the  best  lubricants  we  have: 
of  the  fatty  oils  it  has  the  lowest  viscosity,  and  it  varies 
less  than  that  of  any  other  oil  with  increase  of  tem- 
perature. The  common  adulterants  are  whale,  min- 
eral and  rapeseed  oils,  also  liver  oils.  Whale  oil  is 
indicated  by  the  strong  fishy  odor  and  nutty  taste, 
mineral  oils  by  the  low  flash  test  corresponding  to  a 
gravity  of  0.880,  and  rapeseed  oil  by  the  peculiar  odor 
i and  taste.  It  is  used  as  a  lubricating  and  (formerly) 
as  a  burning  oil. 

Tallow  or  ox  oil  is  obtained  from  beef  tallow  after 
the  manner  of  the  manufacture  of  lard  oil  from  lard. 
It  is  a  light  yellow,  bland  oil,  resembling  tallow  in 
odor,  and  is  employed  in  mixing  with  mineral  oils  as 
cylinder  oil.  . 

Turpentine  is  made  by  the  distillation  of  pine  resin 
or  pitch  in  copper  stills  of  about  800  gallons  capacity. 


178  ENGINE-ROOM    CHEMISTRY 

To  aid  the  process,  a  stream  of  water  is  run  into  the 
still,  making  a  distillation  with  steam:  the  residue  in 
the  still  is  run  off  into  barrels,  forming  the  rosin  of 
commerce.  The  yield  and  quality  vary  according  to 
the  length  of  time  the  trees  have  been  producing  resin, 
both  growing  inferior  with  age.  The  resin  of  the  first 
season  is  called  "virgin  dip/'  and  produces  the  finest 
quality  of  rosin,  "W.W"  (water  white)  or  "W.G." 
(window  glass).  Other  grades  are  "V,"  "U,"  "T," 
etc.,  to  "A,"  which  is  the  poorest  and  blackest. 

Turpentine  is  a  colorless  liquid  of  peculiar  taste  and 
odor:  on  exposure  to  the  air  it  evaporates  and  par- 
tially becomes  resinous.  It  is  adulterated  with  petro- 
leum products  —  benzine  and  kerosene  —  which  would 
be  shown  by  the  low  flash  test  and  gravity,  and  by  the 
bloom  in  the  case  of  kerosene.  Wood  turpentine, 
obtained  from  the  distillation  of  pine  stumps  and  wood 
with  steam,  is  in  many  ways  a  satisfactory  substitute 
for  the  resin  turpentine. 

Whale  oil  is  prepared  from  the  blubber  of  whales  after 
the  manner  of  sperm  oil,  to  which  it  is  similar.  It  has 
a  strong  fishy  odor,  a  nutty  taste,  and  is  light  yellow  to 
brown  in  color.  A  customary  adulterant  is  seal  oil, 
which  it  is  practically  impossible  to  detect.  It  is  used 
as  a  leather  dressing,  as  a  burning  oil,  and  for  lubricat- 
ing purposes. 

Blown  oils.  Blown,  Base,  Thickened  or  Oxidized 
oil  is  usually  prepared  by  heating  the  oil  from  160  to 
230  deg.  F.  in  a  jacketed  kettle  and  forcing  a  current 
of  air  through  it:  after  the  action  is  once  started,  no 
further  heating  is  usually  necessary.  The  color  of 


ANIMAL    AND    VEGETABLE    OILS  179 

the  oil  darkens  somewhat,  but  the  specific  gravity  and 
viscosity  are  much  increased. 

The  oils  submitted  to  this  process  are  chiefly  rape 
and  cottonseed,  making  "Lardine,"  although  it  is 
often  applied  to  linseed,  sperm,  and  seal  oils.  These 
blown  oils  are  used  to  mix  with  other  oils  to  increase 
their  viscosity  for  lubricating  .purposes. 

Besides  these  oils  the  following  are  of  interest : 

Clock  and  Watch  oil.  This  is  obtained  from  the  jaw 
and  head  of  the  blackfish  or  dolphin,  also  an  inferior 
quality  from  the  blubber.  The  oil  is  pressed  after 
the  manner  of  sperm  oil,  bleached  and  refined  by  sun- 
ning in  contact  with  plates  of  lead  to  remove  acid.  It 
is  a  pale  yellow,  very  fluid  oil  of  peculiar  odor:  it  is  the 
highest  in  price  of  any  of  the  lubricating  oils,  being 
worth  from  $5  to  $15  a  gallon  according  to  the  supply. 

Degras.  Properly  speaking,  this  is  a  fish  oil  used  in 
currying  (Moellon),  but  now  applied  to  wool  grease  or 
to  a  mixture  of  wool  grease  and  fatty  acid  from  the 
soap  used  in  scouring  wool.  It  is  made  by  acidifying 
the  settled  washings  from  wool  with  sulphuric  acid, 
separating  the  wool  grease  and  fatty  acid  as  a  more  or 
less  clotted  mass,  which  is  washed,  filtered  off,  and 
pressed  in  screw  presses  heated  by  steam.  Or  the  wool 
is  extracted  with  naphtha,  after  the  manner  of  the  ex- 
traction of  vegetable  oils,  the  naphtha  solution  strained 
and  the  solvent  distilled  off,  leaving  pure  wool  grease. 
This  contains  practically  no  free  acids  nor  sulphuric 
acid,  as  does  the  other,  and  is  a  much  better  product. 
It  is  called  also  "Yorkshire  Grease,"  and  in  a  purified 
form  forms  the  "lanoline"  of  the  apothecaries. 


180  ENGINE-ROOM    CHEMISTRY 

Moellon  is  a  fish  oil,  oftentimes  "cod,"  which  has 
been  oxidized  by  being  absorbed  in  leather.  Chamois 
skins  are  "stuffed"  with  the  fish  oil,  heaped  up,  when 
fermentation  sets  in;  they  are  then  heated  in  water, 
and  pressed,  forming  a  first-quality  product  or  "  French 
degras,"  as  it  is  called.  A  second  quality  is  also  ob- 
tained. 

Neutral  oil  is  a  petroleum  oil  which  is  free  from  flu- 
orescence or  "bloom,"  and  hence  may  be  used  for  the 
adulteration  of  animal  or  vegetable  oils  without  its 
presence  being  evident. 

Screw-cutting  oil  is  a  paraffin  oil  of  27  deg.  B.  mixed 
with  25  per  cent,  of  cottonseed  oil. 

Stainless  oils  are  spindle  or  loom  oils  mixed  with  a 
percentage  of  animal  oil,  as  lard  or  neatsfoot,  so  that 
the  oil  spots  can  be  more  readily  scoured  out  of  the 
goods. 

GENERAL   CONSIDERATIONS    REGARDING    LUBRICANTS 
AND  CHOICE  OF  A  SUITABLE  OIL 

The  following  considerations  will  aid  in  the  selection 
of  a  suitable  lubricating  oil: 

1.  Use  the  most  fluid  oil  that  will  stay  in  place  and 
do  the  work. 

2.  The  flash-point   should   not   be    less   than   300 
deg.  F. 

3.  The    evaporation   test   should    be    less   than    5 
per  cent. 

4.  The  best  oil  is  that  which  possesses  the  greatest 
adhesion  to  metal  surfaces  and  the  least  cohesion  among 
its  own  particles.     These  conditions  are  fulfilled  by 


ANIMAL    AND    VEGETABLE    OILS  181 

mineral  oils,  sperm  oils,  neatsfoot,  and  lard  oil,  in  the 
order  named. 

5.  For  light  pressures  and  high  speed,  use  mineral 
oils  of  30.5  deg.  B.,  flash-point  360  deg.  F.,  also  sperm, 
olive,  or  rape. 

6.  For  ordinary  machinery,  use  mineral  oil  of  25  to 
29  deg.  B.,  flash-point  400  to  450  deg.  F.,  lard,  whale, 
neatsfoot,  tallow,  and  heavy  vegetable  oils. 

7.  For  cylinder  oils,  use  mineral  oils  of  27  deg.  B., 
flash-point  550  to  600  deg.  F.  alone,  and  mixed  with 
small  percentages  (i  to  7)  of  animal  or  vegetable  oils 
as  degras,  tallow,  linseed,  cottonseed,  and  blown  rape. 

8.  For  heavy  pressure  and  slow  speed,  use  lard,  tallow, 
and  other  greases  either  by  themselves  or  mixed  with 
graphite  and  soapstone.    Rosin  greases,  made  by  par- 
tially saponifying  rosin  oil  with  quicklime,  are  also  used. 

The  lubricant  should  be  practically  free  from  acid,  or 
contain  at  most  not  more  than  0.3  per  cent,  figured  as 
sulphuric  anhydride  (SO3),  and  must  be  free  from 
lumps,  which  would  stop  up  the  lubricators.  It  should, 
if  containing  mineral  oil,  be  free  from  tar  and  residue 
insoluble  in  gasolene.  This  test  is  made  by  mixing 
five  cc.  of  the  oil  with  95  cc.  of  86  to  88  deg.  gasolene 
and  allowed  to  stand  for  one  hour:  a  good  oil  should 
not  show  more  than  5  per  cent,  of  flocculent  or  tarry 
matter  settled  out.  It  should  contain  no  "oil-thick- 
ener," "soap,"  "pulp/'  "gelatin,"  or  similar  substance 
added  to  increase  artificially  the  viscosity,  and  should 
be  carefully  strained  into  clean  barrels.  If  the  lubri- 
cant be  compounded,  the  ingredients  should  be  so 
mixed  as  to  give  a  perfectly  homogeneous  product. 


182 


ENGINE-ROOM    CHEMISTRY 


Table  VII  gives  a  more  definite  idea  of  the  constants 
of  oil  which  are  used  for  certain  purposes. 


TABLE   VII 


Kind 

Gravity, 
Deg.  B. 

Flash, 
Deg.  F. 

Fire, 
Deg.  F. 

Viscosity, 
Seconds 

Spindle            .    . 

^O—  3S 

320-300 

58-156-70^ 

Loom 

28 

360 

203-7o°F 

Engine  .  , 

27-30 

410 

475 

190-210-70^. 

Gas  engine  cylinder. 
Cylinder 

26 

23—  2< 

509 

C2<> 

599 
600 

135   at    2i2°F. 

125-141?  2I2°F. 

26-28 

400-575 

2  00-3  O02  1  2°  F. 

In  case  it  is  desired  to  follow  the  subject  further,  the 
following  books  can  be  recommended: 

"Petroleum  and  Natural  Gas/'  transl.  by  W.  T. 
Brannt. 

"Animal  and  Vegetable  Fats  and  Oils,"  transl.  by 
W.  T.  Brannt. 

"  Lubrication  and  Lubricants,"  Archbutt  and  Deeley. 

"Friction  and  Lubrication,"  W.  M.  Davis. 

"A  Short  Handbook  of  Oil  Analysis,"  A.  H.  Gill. 


APPENDIX 


TABLE  VIII 

MELTING-POINTS  OF  VARIOUS  METALS  AND  SALTS  FOR  USE 
WITH  THE  MELTING-POINT  BOXES 


Tin                                          

Deg.  C. 
232 

Deg.  F. 

440 

Bismuth     .                   

268 

"M7 

Cadmium  .  .  .  

320 

608 

Lead  

326 

618 

Zinc  

410 

788 

Cadmium  chloride 

^41 

jOO? 

Aluminum 

6^7 

1  1  ^O 

Potassium  bromide 

722 

1328 

Sodium  bromide 

7">2 

1382 

Potassium  chloride  

800 

1472 

Sodium  carbonate  
Calcium  fluoride 

849 

OO2 

1560 
1648 

Barium  chloride  .  . 

022 

Copper  

io6< 

*you 

183 


1 84 


ENGINE-ROOM    CHEMISTRY 


TABLE  IX 

RELATION  OF  THE  CENTIGRADE  AND  FAHRENHEIT 
SCALES 


Deg.  C. 

Deg.  F. 

Deg.  C. 

Deg.  F. 

Deg.  C. 

Deg.  F. 

o 

32 

65 

149 

1  60 

320 

5 

4i 

70 

158 

170 

338 

10 

5° 

75 

167 

1  80 

356 

15 

59 

80 

176 

190 

374 

20 

68 

85 

185 

200 

392 

25 

77 

90 

194 

220 

428 

30 

86 

95 

203 

240 

464 

35 

95 

IOO 

212 

26O 

500 

40 

104 

no 

230 

280 

536 

45 

"3 

1  20 

248 

300 

572 

5° 

122 

130 

266 

320 

608 

55 

131 

140 

284 

340 

644 

60 

I4O 

15° 

302 

360 

680 

APPENDIX 


185 


TABLE  X 

TABLE  SHOWING  THE  COMPARISON  OF  SPECIFIC   GRAVITY   WITH 
BAUME  DEGREES 


Baume 

Sp.  Gr. 

Baume 

Sp.  Gr. 

10 

I.OOO 

29 

0.88  1 

12 

0.986 

30 

0.875 

14 

0.972 

35 

0.848 

16 

0-959 

40 

0.823 

18 

0.946 

45 

0.800 

2C 

°-933 

5o 

0.778 

21 

0.927 

55 

o-757 

22 

0.921 

60 

o-737 

23 

0.915 

65 

0.718 

24 

0.909 

70 

0.700 

25 

0.903 

75 

0.683 

26 

0.897 

80 

0.666 

27 

0.892 

85 

0.651 

28 

0.886 

90 

0.636 

The  specific  gravity  can  in  general  be  found  by  the 
B°  represents  the  reading    Baume 


formula ^  n 

133  +  B< 

at  60  degrees  F. 


i86 


ENGINE-ROOM    CHEMISTRY 


TABLE  XI 

SHOWING   THE   SPECIFIC   GRAVITY,    DEGREES    BAUME,    WEIGHT 

PER    GALLON    AND  PER  CUBIC  FOOT  OF 

CERTAIN  OILS 


Oils 

Sp.Gr.6o°F. 

Degrees  B. 

Lb.  per  Gal. 

Lb.perCu.Ft. 

Castor   .  .  . 

0.961 

15.66 

8.01 

60.06 

Cottonseed 

.922 

21.83 

7.68 

57.62 

Horse  

.919 

22.17 

7.66 

57-44 

Lard 

.QIZ 

23.00 

7.62 

C7.I4 

Linseed    .  . 

y  o 
•934 

o 

19.87 

/ 

7-79 

»?  /  ***r 

58.37 

Neatsfoot  . 

•915 

23.00 

7.62 

57-T4 

Olive   

.916 

22.80 

7-63 

57-25 

Rape     .  .  . 

.916 

22.80 

7.63 

57.25 

Sperm  .... 

.880 

29.00 

7-34 

55-00 

Tallow  .  .  . 

.916 

22.80 

7.63 

57-25 

Turpentine 

.866 

31.60 

7.22 

54.12 

Whale  

.927 

21.00 

7.72 

57-93 

Water  .... 

I.OOO 

10.00 

8-33 

62.50 

APPENDIX 


187 


TABLE  XII 

SHOWING  THE  VISCOSITY,  FLASH,  VALENTA  AND 
MAUMENE  TESTS  OF  CERTAIN  OILS 


Viscosity 

Flash 

Valenta 

Maumene 

Doolittle, 

Saybolt, 

grams 

seconds 

Deg.  F. 

Deg.  C. 

Deg.  C. 

at  70 

at  70 

deg.  F. 

deg.  F. 

Castor  .  .  . 

viscid 

1321 

345 

20 

47 

Colza  

see  Rape 

— 

— 

— 

— 

Cottonseed 

82.5 

2I02 

582 

90-110 

76 

Horse  .... 

— 



— 

54-  80 

52 

Lard  

82.8 

2I5 

530-600 

54-  98 

4i 

Linseed  .  . 

80.0 

2002 

525 

57-  79 

in 

Neatsfoot  . 

83-7 

250 

440 

62-  75 

42 

Olive  

66 

682 

450 

85-111 

35 

Rape  

86.5 

35o2 

53° 

Insoluble 

55 

Sperm  .  .  . 

73-5 

102 

430-480 

Insoluble 

46 

Tallow  .  .  . 

75-o 

I252 

560 

7i-  75 

35 

Turpentine 

~ 

119-125 

_ 

1  At  140  deg.  F. 

2  Calculated  from  Doolittle  reading. 


i88 


ENGINE-ROOM    CHEMISTRY 


JL 


h m -*{ 


FIG.  47.  —  Flash-point  Apparatus 
for  Lubricating  Oils.      Details 


INDEX 

PAGE 

Acid,  definition  of 9 

hydrochloric : 31,  83 

nitric 31 

sulphuric  31 

Acidity  of  oils,  test  for 146 

Acids  in  boilers 113 

Aluminum,  test  for    33 

Analysis,  gravimetric 13 

proximate 13 

qualitative 12 

quantitative 12 

ultimate 13 

volumetric 14 

Animal  oils,  composition  of 157 

examination  of  162 

obtaining  of 160, 161 

occurrence  of 159 

odor  and  taste  of 164 

test  for  in  mineral  oils 147 

Ammonia 31 

Anthracite  coal,  analysis  of 47,  53 

heating  value 53 

sizes  of 47 

Arndt's  Econometer 95 

Ash  in  coal,  determination  of    56 

Automatic  gas  analysis  apparatus 94 

Atomic  weights 5 

Bases,  definition  of    9 

Basicity  of  acids ,,,,,,.  1 1 


190  INDEX 

PAGE 

Baume  hydrometer    140 

Beakers    24 

Berthier's  method  of  determining  calorific  power  of  coal 61 

Bituminous  coal,  analysis  of 46,  53 

heating  value 53 

Blast-furnace  gas : 70 

analysis  of 72 

heating  value •. 72 

Blowpipe 21 

Boiler  scale 107 

composition  of    1 18 

removal  of  .  „ 108 

testing  of 38 

Briquets 51 

Brown  coal   45 

analysis  of 45 

heating  value 53 

Bunte's  chart  for  loss  in  chimney  gases '. .  93 

Burette 19 

Burner,  Bunsen    •„ . .  20 

gasolene 21 

Calcium  compounds  in  water    102, 131 

sulphate  in  hard  water 126 

test  for 3^ 

in  boiler  water   37 

Calculations 85 

Calorimeters   28 

of  Barrus 59 

Berthelot 60 

Mahler 60 

Norton : 60 

Parr    60 

Thompson,  L 50 

Thomson,  W 58 

Williams  . .  60 


INDEX  191 

PAGE 

Carbon  dioxide,  determination  of 80 

in  coal,  determination  of 57 

Carbonic  acid,  determination  of   80 

generator  for 121 

oxide,  determination  of 80 

Caustic  lime,  use  of 115 

soda,  use  of 115 

Chemical  changes ' 1,2 

reactions • 8 

symbols 3,4 

Chemicals  used  in  burning  coal    73 

Chemistry,  definition  of    i 

Chimney  gases,  apparatus  for  analysis  of 77 

examination  of   74 

sampling    74 

Chlorides,  test  for 37,  131 

Clock  oil 179 

Coal,  air  required  for  combustion 47 

combustion  of 73 

formation  of   44 

gas    71 

analysis  of 72 

heating  value 72 

heating  value 47, 53 

method  of  analysis 54 

sampling    54 

spontaneous  combustion  of 51 

Coffee  mill  . . ., 16 

Coke,  analysis  of   50 

determination  of 56 

heating  value 50 

preparation  of 48 

Coke-oven  gas 50 

analysis  of 72 

heating  value 72 

Coke  ovens   48 


192  INDEX 

PAGE 

Cold  test  of  oils 142 

Corrosion  of  boilers 109 

remedy     1 1 1 

of  iron,  experiments 127 

of  steam  pipes 109 

Crucibles 22 

Crude  petroleum,  flash-test 66 

heating  value 65 

tests  upon    66 

Cuprous  chloride,  acid,  reagent    83 

Custodis  gas  balance    96 

Degras 179 

Dishes,  porcelain 23 

Econometer,  Arndt's  95 

Elaidin  test  166 

Elements   3>  5 


Feed-waters,  tests  applied  to 130 

Filters 23 

Fire  test,  of  burning  oils 152 

of  lubricating  oils 145 

Flash  point   143 

of  burning  oils    15° 

of  lubricating  oils 143 

Flask,  graduated    iQ 

Foaming  in  boilers 113 

Formulas  for  calorific  power  of  coal 63 

Bunte's    64 

Goutal's • 64 

Friction  test *53 

testing  machine,  Thurston's 154 

"Fuel  savers" 73 

Funnels    23 


INDEX  193 

PAGE 

Gas  balance  of  Custodis 96 

composimeter,  Uehling's 97 

producers 67 

pressure 67 

suction 69 

Gaseous  fuels   67 

Gases,  sampling 74 

Gasolene '. 66,  136 

Graduates 18 

Gumming  test 145 

Gypsum  in  hard  water 126 

Halphen's  test 170 

Hard  water 102 

artificial 120 

effects  of    107 

remedies  for    , 114 

softening    106 

Hardness  of  water,  determination  of 104 

Heat  lost  in  chimney  gases 89 

Hydrocarbons,  determination  of   81 

Hydrogen  in  coal,  determination  of    57 

Hydrometer,  Baume 140 

Iodine  test  or  value 172 

Iron  stand 26 

test  for 36 

Lead,  quantity  reduced  measure  of  heating  value 61 

Lignite  45 

analysis  of 53 

heating  value 53 

Lime,  see  also  Calcium 

water,  preparation  of 121 

softening  power  of 115,  124,  126 


I94  INDEX 

PAGE 

Liquid  fuels 64 

heating  value 66 

Litmus  paper   33 

Loss  due  to  carbonic  oxide  formation   93 

to  unconsumed  carbon    94 

of  heat  in  chimney  gases    89 

Lubricants,  specifications  for 148,  180 

Lubricating  oils,  manufacture  of 133 

testing  of 137 

Magnesium  compounds  in  water 103,  131 

test  for 36 

Maumene  test 168 

Melting-point  boxes 28 

of  various  substances 183 

Mineral  oils 132 

chemical  composition  of 157 

test  for  in  animal  and  vegetable  oils    171 

Moellon   : 180 

Moisture  in  coal,  determination  of 55 

Mortar,  iron 16 

Naphtha 66,  136 

Natural  gas,  analysis  of   72 

heating  value 72 

Neutral  oil 180 

Nitrogen  in  coal,  determination  of 57 

Oil,  castor 173 

corn    173 

cottonseed 170,  173 

horse 1 74 

lard 174 

linseed    175 

maize   1 73 

neatsfoot    176 


INDEX  195 

PAGE 

Oil,  rapeseed 176 

rosin 176 

sperm 176 

tallow 177 

turpentine    177 

whale 178 

"  pulp,"  test  for    147 

"thickener,"  test  for   147 

Oils,  blown 178 

Organic  chemistry 1 1 

Orsat's  gas  apparatus 77 

method  of  using 79 

Otto-Hoffman  coke-ovens 48 

Ovens,  drying 23 

Oxygen,  determination  of  in  coal 58 

in  gases    80 

Peat,  analysis  of 44 

briquets   43 

formation  of    43 

gas,  analysis  of 72 

heating  value 72 

heating  value 44 

moisture  in    43 

Petroleum,  distillation  of    133 

obtaining  of 132 

origin  of 132 

refining  of   135 

Physical  changes    1,2 

Physics,  definition  of i 

Pitting    ...    in 

of  iron,  experiments 127 

Potassium  hydrate  reagent 84 

pyrogallate  reagent  . 84 

Pounds  of  air  per  pound  of  coal 86 

Priming  in  boilers    113 


196  INDEX 

PAGE 

Producer  gas 67 

analysis  of 72 

heating  value 72 

Ratio  of  air  used  to  that  theoretically  necessary 88 

Reactions,  chemical 8 

Reagents 30 

Replacing  power  of  elements 10 

Salts,  definition  of  9 

Sampling  coal 54 

chimney  gases 74 

Saponification  number  defined 172 

Scales,  horn-pan 17 

Screw-cutting  oil 180 

Semet-Solvay  coke  ovens   50 

Soap,  effect  of  hard  water  on    124 

solution,  reagent 32 

Soda  ash,  use  of 106,  116,  124 

Sodium  aluminate,  use  of 117, 126 

carbonate,  use  of 116,  125 

fluoride,  use  of 117, 125 

hydrate,  use  of 115 

phosphate  (tri),  use  of 1 18,  125 

Specifications  for  lubricants 148,  180 

Specific  gravity,  definition  of 140 

test 140, 165 

heat,  definition  of 29 

of  gases   91 

of  naphthas 66 

Spontaneous  combustion  of  coal 51 

Stainless  oils 180 

Storage  of  coal 51 

Sulphates,  test  for   36 

in  boiler  scale 22 

in  boiler  water   37, 130 


INDEX  197 

PAGE 

Sulphur  in  coal,  determination  of 57 

Sulphuric  acid  test  for  burning  oils    153 

Symbols • 3>  4 

Table  I,  List  of  common  elements  and  their  atomic  weights. .  5 

II,  List  of  common  compounds  of  the  common  elements  . .  6 

III,  Analyses  of  boiler  scales  from  various  sources. 119 

IV,  Chemical  composition  of  some  boiler  deposits  together 
with  analysis  of  the  feed  waters    120 

V,  Results  of  experiments  to  show  the  rusting  of  steel  nails 

in  artificial   hard  and  polluted  waters  and  in    boiler 

compounds    129 

VI,  Products  from  petroleum 136 

VII,  Constants  of  oils  for  certain  purposes 182 

VIII,  Melting-points  of  various  metals  and  salts  for  use  with 

the  melting-point  boxes 183 

IX,  Relation  of  the  Centigrade  and  Fahrenheit  scales 184 

X,  Comparison  of  specific  gravity  and  Baume  degrees 185 

XI,  Comparison  of  specific  gravity,  degrees  Baume,  weight 

per  gallon  and  per  cubic  foot  of  certain  oils 186 

XII,  Showing  viscosity,  flash,  Valenta  and  Maumene  tests  of 
certain  oils 187 

of  analysis  and  heating  value  of  some  gaseous  fuels 72 

of  hardness    105 

of  heating  value,  flash  and  fire  tests  of  liquid  fuels 66 

of  proximate  analysis  and  heating  value  of  American  coals.  .  53 

Tan  bark,  spent,  calorific  power 51 

"Temporary"  hardness    123 

Test-tubes 24 

Thermometers 27 

testing  of 27 

Thermometer  scales 30 

comparison  of 184 

Turpentine 177 

Uehling's  gas  composimeter 97 


198  INDEX 

PAGE 

Valenta  test 165 

Vegetable  oils,  composition  of 157 

examination  of   162 

obtaining  of 160, 161 

occurrence  of 159 

odor  and  taste  of 164 

test  for  in  mineral  oils 147 

Viscosimeter,  Saybolt's    138 

Viscosity  test 137 

Wash-bottle 25 

Watch  oil 179 

Water,  hard 102 

Water-gas    71 

analysis  of 72 

heating  value 72 

Weighing,  method  of 17 

Wheat  straw,  heating  value 51 

Wood,  analysis  of 43 

gas,  analysis  of 72 

heating  value 72 

heating  value   43 

moisture  in   42 

Yorkshire  grease 1 79 


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